A USGS research study published in the American Geophysical Union's Journal of Geophysical Research sheds light on processes occurring beneath Mount St. Helens.
Measurements at a dozen sites on the volcano during 2010–2016 show a small but steady increase in the strength of Earth's gravity field. The change indicates that material has been added beneath the volcano since the end of the 2004–2008 dome-forming eruption. The gravity increase could be caused by groundwater accumulating in a shallow aquifer that was partly boiled off during the eruption, or by addition of magma to the reservoir-conduit system that fed the eruption, or by a combination of both processes. Of these options, a small influx of magma is consistent with post-2008 seismicity that suggests re-pressurization of the magma system since the eruption ended, something also indicated by geochemical data from hot springs and fumaroles. These results suggest that, although there is no indication of an imminent eruption, the Mount St. Helens magma system remains active and could conceivably erupt again on a time frame of years to decades.
Gravity measurements are another tool used by scientists at the USGS–Cascades Volcano Observatory to better understand volcano behavior and improve eruption forecasts. The gravity surveys provide information about subsurface changes in mass (water or magma) that cannot be obtained by other methods. The results are being combined with data about earthquakes, ground deformation, hot springs, and gas emissions to develop an ever sharper picture of processes that are hidden underground from direct observation.
USGS–CVO continuously monitors activity at Mount St. Helens, along with other Washington and Oregon volcanoes, and provides information and Updates. Read more about repressurization at Mount St. Helens in an Information Statement released April 30, 2014.
What do the Three Sisters, Crater Lake, Medicine Lake, Lassen Peak, Mammoth Mountain and Yellowstone have in common?
Each of these volcanoes has been studied extensively in order to produce comprehensive geologic maps. The results of these studies are more than just maps—each is a synthesis showing a volcanic field's eruptive history and the volcano's behavior over its lifetime. These studies form the foundation for future assessments of volcanic or geologic activity and geohazards.
Take a virtual geologic tour in the USGS Geonarrative, Volcanic Landscapes.
The application process is open for the July 29–August 2, 2018, GeoGirls field camp at Mount St. Helens. The free, week-long science camp targets girls graduating the 7th and 8th grades. GeoGirls, high school mentors, and teacher mentors will spend five days conducting hands-on research and interacting with scientists, learning about volcanoes, natural hazards and modern scientific monitoring technologies. They will camp, hike to field sites, work on research projects and learn how to document and share their scientific findings by building a public webpage.
Applications from middle school girls, high school girls and teacher mentors will be accepted January 3–March 1, with selections announced April 23, 2018. The program will include:
The goal of the program is for GeoGirls participants to emerge with a stronger understanding and connection to Earth systems and feel confident in choosing careers in science, technology, engineering, math or other STEM-related fields. Find all the information you need on the Mount St. Helens Institute webpage. Applications are also accepted for Adult volunteers.
A Magnitude 3.9 earthquake occurred at 12:36 a.m. on January 3, 2018, about 12 km (7.5 mi) NE of Mount St. Helens at a depth of 10 km (6 mi). The earthquake is a tectonic earthquake aligned with regional stress and faulting in the area. There is no sign that this is connected to volcanic activity.
The M 3.9 was followed by a fairly vigorous earthquake aftershock sequence, with at least 15 events located by the Pacific Northwest Seismic Network. Aftershocks tailed off significantly within several hours.
Follow the link to view Mount St. Helens monitoring data online.
The USGS-Cascades Volcano Observatory opens its doors to the public on Saturday, May 12, for a one-day open house. Scientists will be on-hand from 10:00 am to 5:00 pm to share the results of their research and talk about volcano hazards. Hands-on activities and equipment demonstrations will be featured.
Thirty-seven years after the May 18, 1980, eruption of Mount St. Helens, scientists, engineers, land managers, and Federal, State, and County officials are still grappling with a challenge created by the eruption—how to prevent potentially massive downstream flooding by a sudden release of water from Spirit Lake.
A new report from the National Academies of Sciences, Engineering, and Medicine presents a framework to guide federal, tribal, state and local agencies, community groups, and other interested and affected parties in making long-term decisions about the management of the Spirit Lake and Toutle River system. It suggests the process include broad participation by groups and parties whose safety, livelihoods, and quality of life will be affected by decisions about the lake and river system, and that decisions be supported by a quantitative risk assessment, benefit-cost analyses and analyses of other data.
The May 18, 1980 eruption began with an enormous landslide that slammed into Spirit Lake, blocking its natural outlet and raising the lake level by 197 feet. Without an outlet, the water level rose with each rainstorm and seasonal snowmelt, threatening to breach the blockage and produce a catastrophic flood for communities downstream.
To mitigate the hazard, in 1984-1985, the U.S. Army Corps of Engineers constructed an 8,500 foot long, 11 foot diameter tunnel through a bedrock ridge on the west side of Spirit Lake. The lake drains through the tunnel and into the North Fork Toutle River. The tunnel has successfully controlled the lake level since 1985.
Over time, the tunnel has required costly repairs and more are expected in the future. When sections of the tunnel are repaired or upgraded, it is closed for many months and the lake level rises. During each repair, lake levels have approached maximum "safe" levels. If an exceptional weather event, large eruption or major earthquake coincided with an extended tunnel closure that allowed lake levels to rise above 'safe' levels, the lake could potentially breach the blockage and send flood waters downstream. Communities along the Toutle, Cowlitz, and Columbia rivers could be impacted, leading to loss of life and damage of more than $1 billion.
The new report will help management agencies develop long-term solutions to meet the risk-management challenges. The report, A Decision Framework for Managing the Spirit Lake and Toutle River System at Mount St. Helens, is available from the National Academies Press online or by calling 1-800-624-6242. Watch a short video describing the issues.
More information, including a semi-quantitative risk assessment, is available in a publication prepared by U.S. Forest Service and USGS scientists, The geologic, geomorphic, and hydrologic context underlying options for long-term management of the Spirit Lake outlet near Mount St. Helens, Washington.
For over 40 years, scientists have used the latest techniques and technologies to track ground deformation (or surface changes) at Cascade Range volcanoes. The work evolved from sporadic and sparse reconnaissance surveys in the early 1970s to networks of continuously recording GPS stations, semi-permanent GPS stations deployed for weeks to months at a time, and space-based InSAR observations.
The networks, long-term data collection, research, analysis and modeling help shed light on how arc volcanoes work before, during and after eruptions. Here is a brief recap of what's up in the Cascades.
Uplift at South Sister
One volcano has persistent uplift—South Sister. South Sister became the focus of intensive geodetic work in 2001 when InSAR data revealed inflation centered about 6 km (4 mi) west of the summit. The uplift at South Sister is likely related to magma emplacement at a depth of 5-7 km (3-4 mi). The inflation started around 1997 at a maximum rate of 3-5 cm (1-2 in) per year. Since that time, the rate of uplift has declined due to a decrease in the magma accumulation rate, a relaxation of the magma body or a slow release of gases within the magma. Subtle inflation continues as of 2017 but at a low rate of about 5 mm (0.2 in) per year.
Persistent deflation at Mount Baker, Medicine Lake and Lassen volcanic center
Since perhaps as early as the late 1970s, Mount Baker has contracted at a rate of about 1-2 mm (0.04 to 0.08 in) per year. The deflation, which is centered under the volcano's north flank, could be due to the densification of a magma body emplaced in 1975 and/or establishment of a connection between a deep magma body and the surface that allows gases to escape.
Medicine Lake is subsiding at an average rate of about 8-9 mm (0.3 in) per year since at least 1954. The volcano occupies a tectonic setting along the western edge of the Basin and Range extensional province so subsidence is likely the result of crustal thinning due to tectonic extension and a slow sinking of the volcano's mass. Subsidence could also result from cooling and crystallizing of magma bodies at depth.
The Lassen volcanic center is also in an area of tectonic extension. Subsidence of at least 6 mm (0.2 in) per year has been going on since at least the 1980s. The cause of the subsidence is probably a combination of tectonic extension and contraction of the magmatic system or changes in hydrothermal processes.
Uplift and subsidence at Mount St. Helens
Deflation of Mount St. Helens' deep magma system was accompanied by uplift of the crater floor in September 2004, as magma rose to the surface and ultimately erupted. As the 2004-2008 eruption ended, the network around the volcano recorded a transition from deep deflation to subtle inflation due to the repressurization of the magma reservoir. Inflation decayed to background levels by early 2013 and as of 2017, deformation is at or below background levels.
No changes detected at Mount Rainier, Mount Hood, Newberry Volcano, Crater Lake and Mount Shasta
No significant volcano-related deformation has been detected at five volcanoes since the 1980s—Mount Rainier, Mount Hood, Newberry Volcano, Crater Lake and Mount Shasta. This sets an important baseline for future work and will be especially valuable in interpreting the sources of any future unrest.
Additional data needed to assess Glacier Peak, Mount Adams and Mount Jefferson
There are not sufficient data for the remaining three volcanoes for a rigorous assessment—Glacier Peak, Mount Adams and Mount Jefferson. All three volcanoes are located, to some extent, in remote areas, making field work a logistical challenge; a more rigorous analysis would yield a more definitive assessment.
Read more in the article Volcano geodesy in the Cascade arc, USA.
Mount Baker was the focus of a lidar (Light Detection and Ranging) survey that returned high-resolution digital topographic data. These data provide a digital map of the ground surface beneath forest cover, revealing landforms that record the glacial and volcanic history with astounding clarity. The DEM (Digital Elevation Model) dataset and a hillshade image of Mount Baker are now available online in the USGS Data Release: "High-resolution digital elevation dataset for Mount Baker and vicinity, Washington, based on lidar surveys of 2015." The DEM must be opened by software that can read and process GIS data, but the hillshade zip file includes a .tif that can be opened by an image viewer.
Read more and download the data at High-resolution digital elevation dataset for Mount Baker and vicinity, Washington, based on lidar surveys of 2015.
Researchers wrapped up a project at Castle Lake, near Mount St. Helens, mapping the lake bottom and refining measurements of lake volume and surface area. These data will be used in the numerical dam-break models that evaluate potential flood impact to communities downstream of Castle Lake, which include Kid Valley, Toutle, Castle Rock, Kelso, and Longview. While the 65-feet-tall mound of debris that blocked Castle Creek to form Castle Lake is tall enough to retain the lake, a concern remains about whether it is susceptible to other modes of internal failure during extreme hydrologic conditions or during a large earthquake.
The lake formed after South Fork Castle Creek was dammed by the debris avalanche from Mount St. Helens' May 18, 1980, eruption. Almost immediately after the 1980 eruption, the USGS, US Army Corps of Engineers and US Forest Service began evaluating the risk of Castle Lake catastrophically breaching the unconsolidated blockage. An emergency spillway was constructed in late 1980 to stabilize lake-surface elevation. The recent research allows for the computation of lake volume from near real-time lake elevation measurements from a monitoring station or from remotely sensed imagery, and to assess potential downstream hazards.
While most people are aware of the big eruption on May 18, 1980, the volcano continued to have smaller eruptions on May 25, June 12, July 22, August 7, and October 16-18, 1980, that produced pyroclastic flows and other depositional features. USGS geologists were on the scene immediately following the eruptions to map Earth's newest surfaces created by these deposits.
The paper maps they created in 1990 are now available in a modern digital format for use in volcano research. The data release consists of attributed vector features, data tables, and the cropped and georeferenced scans from which the features were digitized, in order to enable visualization and analysis of these data in GIS software.
To read more about these maps and download the GIS data, visit Database for geologic maps of pyroclastic-flow and related deposits of the 1980 eruptions of Mount St. Helens, Washington.
An earthquake swarm began near Mount Hood Monday night ~7 km (4.3 miles) south-southeast of the summit in the White River Valley, an area that commonly exhibits seismicity. It started October 9 at 19:51 UTC (12:51 PDT local) with the largest earthquake a M2.8 at 2:45 UTC on October 10 (1945 PDT on October 9). 14 earthquakes have been located by the Pacific Northwest Seismic Network (PNSN) through October 11, all with depths of 7-8km (4.3 - 5 miles) below sea level.
Such swarms are common in the vicinity of Mount Hood, with the last swarm occurring in May 2016 (largest event M 2.9). Summaries of past swarms near Mount Hood can be found on the PNSN website and on the Mount Hood monitoring webpage.
The Miocene Columbia River Basalt Group (CRBG) is the youngest and best preserved continental flood basalt province on Earth. It is linked in space and time with a compositionally diverse succession of volcanic rocks that partially record the apparent emergence and passage of the Yellowstone plume head through eastern Oregon. This compositionally diverse suite of volcanic rocks are considered part of the La Grande-Owyhee eruptive axis (LOEA), an approximately 185 mile-long volcanic belt located along the eastern margin of the Columbia River flood basalt province. Volcanic rocks erupted from and preserved within the LOEA form an important regional stratigraphic link between the (1) flood basalt-dominated Columbia Plateau on the north, (2) bimodal basalt-rhyolite vent complexes of the Owyhee Plateau on the south, (3) bimodal basalt-rhyolite and time-transgressive rhyolitic volcanic fields of the Snake River Plain-Yellowstone Plateau, and (4) the High Lava Plains of central Oregon.
The guide, Field-trip guide to Columbia River flood basalts, associated rhyolites, and diverse post-plume volcanism in eastern Oregon, describes a 4-day geologic excursion that will explore the stratigraphic and geochemical relationships among mafic rocks of the Columbia River Basalt Group and the compositionally diverse volcanic rocks associated with the early "Yellowstone track" and High Lava Plains in eastern Oregon.
The field guide was developed for the August 2017 International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) Scientific Assembly in Portland, Oregon.
Over the last week, more than 20 earthquakes have been located by the Pacific Northwest Seismic Network at Mount Rainier. In a typical week, Mount Rainier experiences about two "located" earthquakes (to be locatable, earthquakes need to be large enough to be well-recorded on a sufficient number of seismic stations (at least four)), so this represents a modest increase over background rates.
Swarms are a common and expectable occurrence at active volcanoes such as Mount Rainier. While interesting, most never result in surface changes. The most likely scenario for the current swarm is that elevated earthquake rates will continue for a few days before slowly decaying to background rates of seismicity.
The seismicity uptick started late September 11 with a swarm of five earthquakes located 1-2 km (0.5 to 1.5 mi) to the southeast of the summit area. These earthquakes were shallow (up to 2 km (~1.5 mi) above sea level), small (maximum magnitude was a M1.6), and in an area that has not had a lot of previously recorded seismicity. Beginning September 13, earthquakes were also detected about 1 km (~0.5 mi) to the northeast and southeast of the summit, in areas where earthquakes typically occur at Mount Rainier. Depths for these events were 1-2 km (~0.5 to 1.5 mi) below sea level, which is also typical for background seismicity at the volcano, and event magnitudes were small (maximum magnitude 1.2).
In total there have been 23 earthquakes since September 11, with event rates of up to eight located earthquakes per day. Although this is higher than the normal seismicity rates at Mount Rainier, it is not unprecedented. Over the past 10 years there have been three previous periods with similar or higher event rates (September 2009, April 2015 and May 2016). Current event rates are similar to those seen in April 2015 and May 2016, but are far smaller in rate, energy release, and total number of earthquakes than what was seen in September 2009, when a swarm featuring hundreds of located earthquakes occurred over a three-day period. For the current swarm, earthquake location, depth, and size are all consistent with background seismicity; the only thing that is different is the event rate.
These earthquakes are inferred by scientists to be caused by processes occurring in Mount Rainer's hydrothermal system. The hydrothermal system is the region beneath the volcano containing hot mineral-rich water; one manifestation of this system is the boiling-point fumaroles that are found at the volcano's summit. Similar to pipes in geothermal plants, cracks transporting water away from a hot source may seal shut as the water cools and loses its dissolved minerals. Earthquakes are created when sufficient fluid pressure builds behind these seals to fracture them.
Each swarm provides seismologists with more perspective on the personality of the volcano and aids in our ability to assess hazards in the future. As always, scientists at the USGS Cascades Volcano Observatory and Pacific Northwest Seismic Network will continue to monitor the situation and provide updates as conditions warrant.
Use this link to learn more about Monitoring Mount Rainier.
Between August 19 and 22, seismologists with the USGS-Cascades Volcano Observatory, University of New Mexico, University of Oregon, University of Wisconsin-Madison, Cornell and Northwestern worked together to install 140 temporary seismometers at Mount St. Helens. Instruments were placed on top of the lava dome that erupted in 2004-2008, as well as the 1980-86 lava dome, the 1980 crater floor, and around the volcanic cone. The goal of the month-long deployment is to capture small magnitude volcanic earthquakes and learn more about the shallow plumbing system beneath the crater floor.
The project represents the largest number of seismometers ever placed on a U.S. volcano. The seismometers, which resemble an insulated big-mouth thermos with spikes on the bottom, weigh only six pounds, are self-contained, and are easy to deploy. The seismometers store data on a small internal computer and have enough battery power to operate for about one month.
"The goals of the project are to more precisely locate and characterize the small-magnitude volcanic earthquakes that routinely occur at St. Helens. We also want to be able to more reliably discriminate volcanic earthquakes from rockfalls off the crater wall, which have a similar seismic signature in many cases," said Wes Thelen, a seismologist with the USGS-Cascades Volcano Observatory. "Once we collect the data and have a better idea about what is occurring in the shallow subsurface, we will be able to compare those signals with signals recorded on our permanent network stations to recognize and identify earthquake sources when they happen again."
The data will augment the results of the recently completed iMUSH (imaging Magma Under St. Helens) experiment. The equipment used in iMUSH looked "deeper" than a mile (2 km), whereas this project looks at shallow earthquakes that occur between the surface and 2 km. A number of earthquakes and rockfalls have already occurred since the instruments were deployed.
Mount St. Helens is the most seismically active volcano in the Washington and Oregon Cascades. In an average month about 20 events are located by the Pacific Northwest Seismic Network, with the number going far higher during eruptive periods. Seismologists have also tracked several shallow earthquake swarms at Mount St. Helens since the eruption ended in 2008, most recently in May of 2017. Generally, swarms consist of tens to hundreds of earthquakes with magnitudes less than M1.5 and depths between 1 and 4 miles (2 to 7 kilometers) below the surface. These swarms are believed to be associated with the ongoing magma recharge of the plumbing system beneath Mount St. Helens, but are not an indication that an eruption is imminent.
Crews will return to Mount St. Helens on September 20-22 to retrieve the equipment and collect the data. Use this link to learn more about Monitoring Instruments and Data at Mount St. Helens.
Mount St. Helens has been referred to as a "master teacher." The 1980 eruption and studies both before and after 1980 played a major role in the establishment of the modern USGS Volcano Hazards Program and our understanding of flank collapses, debris avalanches, cryptodomes, blasts, pyroclastic density currents, and lahars, as well as the dynamics of magma ascent and eruption.
The guide, Field-Trip Guide to Mount St. Helens, Washington—An Overview of the Eruptive History and Petrology, Tephra Deposits, 1980 Pyroclastic Density Current Deposits, and the Crater, provides an overview of the eruptive history of Mount St. Helens, and the volcanologic and petrologic insights resulting from studies of the 1980-86 and 2004-2008 lava domes. The guide describes the dynamics and progressive emplacement of pyroclastic flows, classic tephra outcrops of the past 3,900 years and how the petrology and geochemistry of Mount St. Helens deposits reveal the evolution of the magmatic system through time.
The field guide was developed for the August 2017 International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) Scientific Assembly in Portland, Oregon.
The crest of the Oregon Cascade Range has an average elevation of 5,000 to 6,500 ft, with several of the highest volcanoes exceeding 9,000 ft. The volcanoes intercept moisture from the Pacific Ocean, which falls as rain or snow on the west side of the crest. But to the east, the Cascades create a rain shadow—one of the strongest precipitation gradients in the lower 48 states. Forests east of the crest are a mix of alpine and subalpine hemlocks and firs that transition abruptly into a more open forest of ponderosa pine and lodgepole pine in response to the abrupt decline in rainfall.
Although the focus of this multidisciplinary field trip is on mafic volcanism, it also looks at hydrology, geomorphology, and ecology, and how these elements both influence and are influenced by mafic volcanism. The trip includes travel up the valley of the McKenzie River, the mafic volcanic rocks at the Sand Mountain volcanic field and in the Santiam Pass area, at McKenzie Pass, and in the southern Bend region. Download the Field-trip guide to mafic volcanism of the Cascade Range in Central Oregon—A volcanic, tectonic, hydrologic, and geomorphic journey, for a 6-day trip to central Oregon.
The field guide was developed for the August 2017 International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) Scientific Assembly in Portland, Oregon.
Mount Mazama rose to an elevation of over 12,000 ft before its collapse during a rapid series of explosive eruptions about 7,700 years ago. The climactic eruption devastated the terrain for tens of miles, sent pyroclastic flows into every drainage, and produced ash fall throughout much of the Pacific Northwest. Since that eruption, volcanism has been confined within the caldera and most of the volcanic products are hidden from view beneath Crater Lake.
This field guide takes you to locations both inside and outside Crater Lake National Park, where you can see superb exposures of lava flows and pyroclastic deposits, with accompanying descriptions that give exceptional insight into how large volcanoes of magmatic arcs grow and evolve. Follow the driving instructions in the Geologic field trip guide to Mount Mazama and Crater Lake Caldera, Oregon, during your next visit.
The Pacific Northwest is host to an incredible volcanic landscape. This 4-day field trip guide gives a broad overview of the region's diverse volcanism, focusing on Columbia River Basalts, High Lava Plains, and Cascade Range volcanic features.
The trip begins with an examination of lava flow structures of the Columbia River Basalt—enormous lava fields that were emplaced during one of the largest eruptive episodes in Earth's recent history. On the second day, the trip turns to the High Lava Plains, a bimodal volcanic province that provides excellent examples of welded ignimbrite, silicic lavas and domes, monogenetic basaltic lava fields, and hydrovolcanic features. The third day is devoted to a circumnavigation of Crater Lake, the result of caldera-forming eruptions of Mount Mazama. The last day is spent at Newberry Volcano, a shield volcano topped by a caldera. Newberry is compositionally bimodal with an abundance of explosive and effusive deposits, including the youngest rhyolites in the Pacific Northwest. Download the complete guide, Field-Trip Guide to a Volcanic Transect of the Pacific Northwest, to begin the adventure.
Newberry Volcano is a massive, shield-shaped, composite volcano in central Oregon. Eruptions began about half a million years ago and built a broad edifice that has generated more than one caldera collapse. About 75,000 years ago, a major explosive eruption and collapse event created a large volcanic depression at its summit that now hosts two caldera lakes—Paulina and East Lakes.
A significant mafic eruptive event occurred about 7,000 years ago along the northwest rift zone. This event produced lavas ranging in composition from basalt to andesite, some of which traveled over 20 mi to Lava Butte, to temporarily block the Deschutes River.
The Field-Trip Guide to the Geologic Highlights of Newberry Volcano, Oregon, takes the visitor to a variety of easily accessible geologic sites in Newberry National Volcanic Monument, including the young, spectacular flows of rhyolitic obsidian. Side trips include a visit to the Lava Cast Forest, Lava River Cave, Lava Butte, Benham Falls, Pilot Butte and the Peter Skene Ogden Scenic Wayside, with annotated images and descriptions that offer an overview of the geologic story of Newberry Volcano.
On August 15, 2017, join us at the Oregon Museum of Science and Industry (Portland) for the evening Science Pub program "Nature's Fury: Living with Active Volcanoes."
Three renowned scientists, John Ewert (USGS-Cascades Volcano Observatory), Marta Calvache (Colombian Geological Survey) and Richie Robertson (University of West Indies), will share their experiences studying and responding to volcanic eruptions. Hear how advances in volcano science and lessons learned are applied globally and at our Cascade volcanoes.
This event is presented by the Oregon Museum of Science and Industry, U.S. Geological Survey, USGS-U.S. Agency for International Development, Office of U.S. Foreign Disaster Assistance, Volcano Disaster Assistance Program, U.S. Forest Service, and the Mount St. Helens Institute. Details are available at OMSI.
Obsidian-rich lava flows have been of interest to geologists, archaeologists, pumice miners, and rock hounds for more than a century. But active rhyolitic obsidian lava flows have never been scientifically witnessed and lively debate ensues at outcrops over the formation of some lava flow features.
At first glance, the surface of an obsidian flow appears to be a chaotic mixture of blocks, spines and hillocks of different colors, sizes, densities, crystallinity and vesicularity. However, on aerial photos (or after one stumbles around for a few hours), patterns begin to emerge. Folds and ridges are caused by flow-parallel compression. Three main textures appear on the flow front—finely vesicular pumice carapace, dense obsidian and coarsely vesicular pumice.
This new field guide takes you to locations at Newberry, South Sister and Medicine Lake Volcanoes, to examine the textural and structural characteristics of silicic lava flows. Download Emplacement of Holocene silicic lava flows and domes at Newberry, South Sister, and Medicine Lake volcanoes, California and Oregon for your next journey to central Oregon and northern California.
On the afternoon of May 18, 1980, pyroclastic density currents (PDCs) spilled over the crater rim and poured through the breach created in Mount St. Helens' north flank. At times, the PDCs collided, scoured and filled channels, laid down beds 40 feet (12 m) thick and traveled as much as 5 miles (8 km) from the vent.
Our ability to interpret the deposits is critical for understanding transport and depositional processes that control PDC dynamics—one of the most dangerous phenomena associated with explosive volcanism. The results of extensive work on the May 18, 1980, PDC deposits show that slope and irregular topography strongly influence PDC flow path, dynamics, criticality (for example, supercritical versus subcritical), carrying capacity, and erosive capacity. However, the influence of these conditions on ultimate flow runout and damage potential warrants further exploration through the combination of field, experimental, and numerical approaches.
This field guide describes the PDC deposits at Mount St. Helens and poses questions for further research. Download Field-trip guide for exploring pyroclastic density current deposits from the May 18, 1980, eruption of Mount St. Helens, Washington to learn more.
Partly situated in Mount Rainier National Park, this field trip guide visits exceptional examples of volcaniclastic successions laid down in continental basins adjacent to the ancestral Cascades arc. The Ohanapecosh Formation (32–26 Ma) and the Wildcat Creek (27 Ma) beds record similar sedimentation processes from various volcanic sources. They show evidence of probable Surtseyan eruptions, tephra fallout over water, entrance of pyroclastic flows into water, scoria-cone building eruptions in shallow water, and resedimentation events. The field trip examines outcrops along White Pass, Cayuse Pass, Chinook Pass and at Burnt Mountain.
Download Field-Trip Guide to Subaqueous Volcaniclastic Facies in the Ancestral Cascades Arc in Southern Washington State—The Ohanapecosh Formation and Wildcat Creek Beds for your next road trip to this area.
Starting and ending in Portland, Oregon, this new field trip guide describes stops of geologic interest for a 175-mile adventure around the Mount Hood volcano.
Mount Hood is a 500,000-year-old composite volcano. Unlike Mount St. Helens, Mount Hood has not produced highly explosive eruptions. Rather, it has erupted andesite and (rarely) low-silica dacite lava flows and domes that have built the 11,241-feet-tall volcano. Pyroclastic flows triggered by the collapse of growing lava domes have generated lahars that swiftly melted snow and ice, as well as lahars generated by large landslides, that have surged tens of miles down valleys.
Use this guide to investigate the outcrops and unique features of Mount Hood, learning more about its history and how this active volcano may behave in the future. Download Field-trip guide to Mount Hood, Oregon, highlighting eruptive history and hazards and plan your next visit to the volcano.
The Columbia River Basalt Group covers an area of more than 81,000 square miles. As the youngest continental flood-basalt province on Earth (16.7–5.5 Ma), it is well preserved, with a coherent and detailed stratigraphy exposed in the deep canyonlands of eastern Oregon and southeastern Washington.
This new field trip guide begins in southeastern Oregon near Burns, progresses northward into southeastern Washington, continues in the Pasco Basin and ends in the Columbia River Gorge near Stevenson, Washington. The excursions are arranged progressively from the oldest to the youngest units found in the heart of the flood-basalt source region. The road log examines the stratigraphic evolution, eruption history, and structure of the province through a field examination of the lavas, dikes, and pyroclastic rocks of the CRBs.
Download Field-trip guide to the vents, dikes, stratigraphy, and structure of the Columbia River Basalt Group, eastern Oregon and southeastern Washington and plan your summer trip.
As many in the Pacific Northwest can attest to, the winter of 2017 has been a rough one. Deep snow in the high country buried volcano monitoring sites and caused loss of telemetry and/or power. These problems reduced the Mount St. Helens seismic network, operated jointly by the Cascades Volcano Observatory (CVO) and the Pacific Northwest Seismic Network (PNSN), to roughly half its normal operating capacity. The consistently bad weather prevented CVO and PNSN staff from performing any mid-winter repairs.
A clear weather day on April 21, permitted CVO and PNSN personnel to visit Mount St. Helens and restore the seismic network to nearly full capacity. Immediately after repairs were made, the PNSN began locating small earthquakes at relatively high rates (1 earthquake every few hours) under Mount St. Helens. The damage to seismic stations reduced the ability of the seismic network to locate small-magnitude earthquakes, at least somewhat.
Further analysis has revealed that many of the earthquakes look similar to each other, a common feature of swarms at Mount St. Helens and a sign that the events are occurring in close proximity. Using data from stations operable all winter, CVO scientists used the repeating characteristic of the earthquakes located since April 21 to track down when the swarm started. The result? There is good evidence that the uptick began as early as April 16 and definitely was occurring as of April 18.
As of May 5, the PNSN has located 47 earthquakes near Mount St. Helens since the seismic network was restored on April 21. Utilizing the similarity of earthquakes, we can detect well over 100 earthquakes that are part of this swarm. Most earthquakes have depths between sea level and 3 mi (5 km) below sea level (approximately 2-7 km below the surface). This is consistent with depths of earthquakes occurring since 2008, which are thought to be in response to recharge in the magmatic system. Earthquake rates, though relatively high compared to background, are still only 1 earthquake every few hours, a rate that is consistent with past small swarms since 2008. All earthquakes are volcano tectonic in character (no detected low-frequency or long period earthquakes) and the maximum magnitude thus far is a M1.3. There is no detectable deformation or gas signal associated with this swarm.
Similar swarms occurred at Mount St. Helens in March-May 2016 and November 2016. Both swarms had repeating earthquakes, average rates of 1-2 earthquakes/hour, and most earthquakes with magnitude below M1.5.
The similarity of swarms at Mount St. Helens leads us to believe that similar processes cause them, and they are likely tied to magma recharge first detected in 2008. However, pinpointing that exact process is difficult. Some possible mechanisms include a spontaneous release of brine from the pressurized magma chamber into the crust above, a pulse of magma into the magma reservoir that transferred stress into the crust above, or just the breakage of a new pathway of fluid flow that was previously blocked by precipitated minerals. There are several reasons why it is very unlikely that this swarm is a precursor to imminent eruptive activity at Mount St. Helens—it is similar to ones in the past that did not lead to surface activity; it consists of very small earthquakes occurring at relatively low rates; there are no other geophysical indicators (deformation, tilt, gas) of unrest.
For the month of May, residents in the State of Washington will have the opportunity to become more familiar with volcano hazards in their communities and learn about steps they can take to reduce potential impacts. The USGS in cooperation with Washington State Department of Natural Resources, Washington Emergency Management Division, and the Pacific Northwest Seismic Network have created a variety of products and programs to bring awareness to the state's five main potentially active volcanoes.
May is also the month to commemorate the May 18, 1980 catastrophic eruption of Mount St. Helens, which not only caused massive destruction and loss of life but also became a catalyst for a new era of unprecedented scientific discovery, technology development and community awareness. Follow USGS Volcanoes on Facebook or Twitter to see photographs and news articles and read eye-witness accounts of events as they unfolded 37 years ago.Read the full USGS Press Release to learn more about events.
One of the most tragic volcanic events of the 20th century occurred in Colombia, in 1985, when an eruption of Nevado del Ruiz produced lahars that swept down river valleys and destroyed communities in their paths.
Mount Rainier and other volcanoes of the Pacific Northwest's Cascade Range are similar to Nevado del Ruiz in many respects – massive amounts of snow and ice, a long history of lahars, and narrow valleys leading to populated areas. Could what happened at Nevado del Ruiz happen here? And if it did, are we prepared?
Colombian geologist Dr. Marta Calvache, Director of Geohazards Mitigation at the Servicio Geológico Colombiano, will tell an encouraging story of effective lahar evacuation in Colombia. Her message: community awareness and drills do count. The free event will be held Thursday, May 4, 2017, from 6:00 pm to 8:00 pm, at the Orting High School Performing Arts Center, Orting, Washington.
Mount Rainier offers beauty, mystery, inspiration, and challenge. Satisfy your curiosity, connect with colleagues, and find fresh ideas for your classroom at this one-day teacher workshop in Orting, Washington, on March 25.
This workshop features informative talks about volcanic hazards, hands-on volcano activities for the classroom, tips on how to organize a field trip into the Park, and ideas for what to do at your school during May's Volcano Awareness Month. Alumni from past Mount Rainier teacher workshops are encouraged to attend and share how they teach about the volcano.
The free workshop is Saturday, March 25, 2017, from 8:00 am to 4:00 pm at Orting Middle School. Seven clock hours are available. To register, contact Fawn Bauer at Fawn_Bauer@nps.gov or by phone at (360) 569-6591.
The application process is open for this year's GeoGirls field camp at Mount St. Helens. The free, week-long science camp targets girls graduating the 7th and 8th grades and will be held July 30–August 3. The program is a collaborative effort between the U.S. Geological Survey and Mount St. Helens Institute, along with partners from the Washington State Department of Natural Resources, UNAVCO, University of Washington and Oregon State University. Applications from girls, female high school students and teacher mentors will be accepted March 8–April 5. More information and application procedures are available at the Mount St. Helens Institute.
Mount Rainier National Park is a unique classroom, rich in resources for observing geologic change. Join us July 17–21, 2017, for a 5-day educator workshop in the Park, where we will explore the diverse and dynamic processes that have shaped the volcano and share new classroom ideas that will engage middle school students. There is a $20 fee for this workshop and free camping is available to participants. Registration information is at the Mount Rainier Teacher Professional Development webpage.
Four swarms of small magnitude earthquakes were detected beneath Mount St. Helens beginning November 21, 2016. No anomalous gases or increases in ground inflation have been detected and there are no signs of an imminent eruption.
During a week's time, there have been over 120 tiny earthquakes, most too small to be formally located by the Pacific Northwest Seismic Network. The earthquakes are magnitudes 0.3 or less; the largest has been a magnitude 0.5. Most of the earthquakes are occurring in the shallow volcano plumbing system about 1-2 miles below sea level. These earthquakes are too small to be felt at the surface.
The current pattern of seismicity is similar to swarms most recently seen at Mount St. Helens in March-May 2016, and in 2014 and 2013. The magmatic system is likely imparting its own stresses on the crust around and above it, as the system slowly recharges. The stresses drive fluids through cracks, producing the small quakes. Subtle evidence of recharge has been observed since 2008 and can continue for many years. It is a sign that Mount St. Helens remains an active volcano.
For more information, see the Activity Updates for Volcanoes in CVO Area of Responsibility and Earthquake Monitoring at Mount St. Helens.
The western Columbia Gorge has been long recognized as an area susceptible to landslides. Abundant rainfall, steep terrain, geologic structure and erosion by the Columbia River combine to create topography capable of ground movement. Yet dense forests have hampered efforts to accurately map old and currently active landslides and to fully understand the scope of this hazard.
A new study uses lidar to map and characterize known and previously unrecognized landslides in the western Columbia Gorge, Washington. Lidar is a remote-sensing technique that provides images of terrain from which vegetation and structures can be digitally "erased" to show the underlying bare ground. Formerly hidden by forest, lidar reveals telltale landslide indicators such as scarps, cracks and ridges, slope depressions, bulges and toes.
The imagery shows that landslides cover about two thirds of the 222 square km (86 square mi) map area. Two of the largest landslides in the map area—the Bonneville and Red Bluffs landslides, averaging about 75 m (250 ft) thick with runouts of 6-7 km (~4 mi)—failed catastrophically and slid rapidly to the river within the last 600 years; the Bonneville landslide temporarily dammed the Columbia River and formed the "Bridge of the Gods" known from Native American legends.
Research shows that these landslides have complex movement histories and have been active over thousands of years; some have moved recently or are currently moving. Another such landslide rapidly sliding into the Columbia River today could have a catastrophic impact on downstream communities and on the transportation and energy-distribution infrastructure of the Pacific Northwest.
The publication, Landslides in the western Columbia Gorge, Skamania County, Washington, is available online.
Much is known about the shallow magmatic system beneath Mount St. Helens. But as you go deeper, the picture is less clear. New research suggests that temperatures 40-50 miles beneath the volcano are too cold to generate magma. Yet, Mount St. Helens is the most active in the Cascade Range, erupting catastrophically on May 18, 1980 and producing two dome-building pulses from 1980-86 and 2004-08. So where does the magma come from?
In a recent article from researchers at the University of New Mexico, Rice, University of Washington, Cornell and University of Arizona, the dataset from seismic experiments conducted in 2014 for the collaborative iMUSH program (Imaging Magma Under St. Helens) show that Mount St. Helens sits atop a cold hydrated mantle wedge (less than 1300 degrees F) produced by subduction of the oceanic plate. The temperature of the wedge is too cold to be part of the process that forms magma to feed Mount St. Helens. A primary conclusion of this article is that magma is generated somewhere to the east of the volcano, with magma at some point moving west into Mount St. Helens' magmatic system. More studies are needed to determine the lateral pathway(s) necessary for the magma to reach the shallow reservoir beneath the crater floor. Additional iMUSH results are expected to be published in the coming months.
Follow the link for more information on the eruptive history of Mount St. Helens.
Newberry is a broad shield-shaped volcano in central Oregon that rises a mile above sea level. It has been constructed by thousands of eruptions, including at least 25 in the last 12,000 years.
To better understand Newberry's past and assess future hazards, the USGS worked with the Oregon Department of Geology and Mineral Industries and Oregon Lidar Consortium to obtain 500 square miles of high-precision airborne lidar (Light Detection and Ranging) data at and around Newberry. These data provide a digital map of the ground surface beneath forest cover, revealing landforms with astounding clarity. The lidar-derived Digital Elevation Model (DEM) of the area also includes bathymetric surveys of East Lake and Paulina Lake.
The DEM dataset, High-resolution digital elevation dataset for Newberry Volcano and vicinity, Oregon, based on lidar survey of August-September, 2010 and bathymetric survey of June, 2001, is available online. The individual DEMs must be opened by software that can read and process GIS data. The hillshades zip file includes tifs that can be opened by an image viewer.
In the early morning hours of September 23, 2004, a swarm of small-magnitude earthquakes about half a mile below Earth's surface marked the reawakening of Mount St. Helens after 18 years of eruptive quiescence. Steam and ash explosions on October 1 were followed by three years of lava extrusion that formed a new dome inside the crater. The lava dome pushed Crater Glacier aside, causing it to flow rapidly toward the front of the 1980 breach; flow continues today.
Scientists at the USGS-Cascades Volcano Observatory and its partners used many techniques during the 2004-2008 eruption to monitor the volcano, including interpretation of seismicity, ground deformation, thermal imaging, time lapse photography and lava sampling. Because of its location, easy access, and varied styles of eruptions, Mount St. Helens has become our 'go-to' volcano for development and testing of monitoring devices and techniques. Lessons learned at Mount St. Helens have been shared with researchers around the world to better understand volcano behavior, assess hazards and potential impacts, and provide timely warnings of future events.Read more in USGS Professional Paper 1750, chronicling the renewed eruption of Mount St. Helens (2004-2006). Follow the link for a brief recap of 2004-2008 events.
Every year, Mount St. Helens gets an average of 162 inches of rain and about 40 feet of snow. So where does all the water go? Some of it enters rivers and streams that originate on the volcano and some of it enters the groundwater system. USGS researchers used the Earth's naturally-occurring electromagnetic energy, specialized instrumentation and data processing techniques to find groundwater at Mount St. Helens, learning more about where it flows.
Using a geophysical method called Controlled-Source Audio-Magnetotellurics, researchers located two aquifers at Mount St. Helens. There is a deep conductor (the top of which is at a depth of about 1600 ft), interpreted as the regional aquifer that mounds up beneath the edifice. There is also an overlying separate, relatively thin but much more conductive body at a depth of about 100-160 ft that appears to be recharged by meltwater from Crater Glacier and heated by hot rock beneath the 2004-08 dome. The higher ionic content of the shallow aquifer may come from dissolved volatiles from the cooling dome and hydrothermal alteration. The CSAMT soundings extending north of the volcanic to the upper North Fork Toutle River show that these aquifers remain separate but eventually merge farther to the northwest into a single conductor (or groundwater system).
Knowing more about groundwater at Mount St. Helens is useful in understanding the hydrologic system and in interpreting seismicity. This research develops a baseline for Mount St. Helens that can be compared to future years to understand more about the evolving groundwater system and its effect on the volcano.Read more at Where is the Hot Rock, and Where is the Groundwater—Using CSAMT to Map Beneath and Around Mount St. Helens.
USGS and its partners invite educators to join us for a fun and informative teacher workshop at Mount St. Helens' Coldwater Science and Learning Center, June 22 to 24, 2016. This three-day classroom and field-based workshop offers science information, hands-on classroom activities, and resources that will enrich your understanding of the Cascade Range and aid in your ability to lead an informative student field trip to this active volcano. Clock hours are available.
Visit the Mount St. Helens Institute Teacher Workshop webpage to register.
May 18 marks the 36th anniversary of the catastrophic eruption of Mount St. Helens. The eruption remains a seminal historical event; studying it and its aftermath revolutionized the way scientists approach the field of volcanology. Not only was the eruption spectacular, it occurred in daytime, at an accessible volcano, in a country with the resources to transform disaster into scientific opportunity, amid a transformation in digital technology. Lives lost and the impact of the eruption on people and infrastructure downstream and downwind made it imperative for scientists to investigate events and work with communities to lessen losses from future eruptions. Follow the signs and symptoms of volcanic unrest that led to the May 18, 1980 eruption in the volcano activity update archives. Sign up with the Volcano Notification Service to receive news of current activity and join the discussion on USGS Volcanoes Facebook.
At Mount Hood, a swarm of small earthquakes was detected May 15-16, 2016. Studies of past swarms have concluded that they likely are occurring on pre-existing regional faults and are best thought of as "tectonic" earthquakes rather than earthquakes directly linked to magmatic processes.
The earthquakes in this swarm are located 2-3 miles south of the summit of Mount Hood at depths of 2-3 miles below sea level. The largest event was a magnitude 1.8. Earthquake rates reached as many as 20 earthquakes per hour, peaking between 6-7 am on May 16 before decreasing later in the day. The Pacific Northwest Seismic Network (PNSN) located nearly 60 earthquakes; many more events occurred that were too small to be located. This swarm is very typical for Mount Hood because it is located several miles away from the summit vent – it is rare to see swarms occur directly beneath the summit.
Swarms are not uncommon in the Mount Hood area, which typically experiences one or two swarms per year that last for several days to weeks. The most energetic swarm recorded to-date occurred in June-July of 2002, which included a magnitude 4.5 that was broadly felt in the Government Camp area. The current swarm is much, much smaller than the 2002 swarm, both in terms of earthquake size and in number. A paper published in 2005 by J. Jones and S.D. Malone studied Mount Hood swarms in great detail; read more in a PNSN 2012 blog.
Beginning March 14, 2016, a number of small magnitude earthquakes have occurred beneath Mount St. Helens, at a depth between 2 and 7 km (1.2 to 4 miles). Over the last 8 weeks, there have been over 130 earthquakes formally located by the Pacific Northwest Seismic Network and many more earthquakes too small to be located. The earthquakes have low magnitudes of 0.5 or less; the largest a magnitude 1.3. Earthquake rates have been steadily increasing since March, reaching nearly 40 located earthquakes per week. These earthquakes are too small to be felt at the surface.
The earthquakes are volcano-tectonic in nature, indicative of a slip on a small fault. Such events are commonly seen in active hydrothermal and magmatic systems. The magma chamber is likely imparting its own stresses on the crust around and above it, as the system slowly recharges. The stress drives fluids through cracks, producing the small quakes. The current pattern of seismicity is similar to swarms seen at Mount St. Helens in 2013 and 2014; recharge swarms in the 1990s had much higher earthquake rates and energy release.
No anomalous gases, increases in ground inflation or shallow seismicity have been detected with this swarm, and there are no signs of an imminent eruption. As was observed at Mount St. Helens between 1987-2004, recharge can continue for many years beneath a volcano without an eruption.For more information, see the Activity Updates for Volcanoes in CVO Area of Responsibility and Earthquake Monitoring at Mount St. Helens.
On March 14, 2016, the seismic network at Mount St. Helens began detecting small magnitude earthquakes at a depth of 3–4 km beneath the crater. Twelve earthquakes have been formally located and the local seismic network detected at least 100 earthquakes too small to be recorded on enough seismometers to calculate a location. Many of the earthquakes have similar seismic signatures, suggesting they are occurring in the same area as the located earthquakes. According to the Pacific Northwest Seismic Network, the largest earthquake over a four-day period was a Magnitude 0.7, an event that would not be felt even if you were standing on the surface above it.
These types of volcano-tectonic earthquakes beneath Mount St. Helens are likely associated with the recharge of the volcano. After the 2004-2008 eruption, subtle inflation of the ground surface and seismicity indicate that the magma reservoir beneath Mount St. Helens is slowly re-pressurizing, as it did after the conclusion of the 1980-1986 eruption. This is to be expected and it does not indicate that the volcano is likely to erupt anytime soon. Re-pressurization of a volcano's magma reservoir is commonly observed at volcanoes that erupted recently, and recharge can continue for many years without an eruption. For more information, see the Activity Updates for Volcanoes in CVO Area of Responsibility and Earthquake Monitoring at Mount St. Helens.
Join us July 25–29, 2016, for a 5-day educator workshop at Mount Rainier. The workshop features informative talks on Cascade volcanoes and volcanic processes, ideas for classroom activities, hikes into the field, and tips for organizing school field trips to visit the volcano. There is no charge for this workshop and camping is available to participants. Registration information is at the Mount Rainier Teacher Professional Development webpage.
The Community Foundation for Southwest Washington, in cooperation with the U.S. Geological Survey's Volcano Science Center, invites applications for the 2016 Jack Kleinman Volcano Research Grants Program. Stipends of $500 to $2,000 are available to senior undergraduates and graduate students who are conducting research in volcanology, preferably in the Cascade Range, Aleutian volcanic arc, Hawaii, Yellowstone, or Long Valley caldera. Read the detailed grant application instructions to find out more.
A new geologic map and pamphlet provides information on a young volcanic field of intraplate basalts located just east of the Cascade Arc—the Simcoe Mountains volcanic field, in south-central Washington State.
The map shows, in various colors, the areas covered by 223 different eruptive units, mostly lava flows and cinder cones ranging in age from ~4 million to 600,000 years old. Most of these units were produced by short-lived (a few years) basaltic eruptions that featured localized lava fountains and/or lava flows that extended at most several miles, creating small volcanic cones that are now extinct. The only large long-lived volcano in this field capable of erupting again in the future is Mount Adams, located on the western boundary.
Read more in Scientific Investigations Map 3315, Geologic Map of the Simcoe Mountains Volcanic Field, Main Central Segment, Yakama Nation, Washington. This product was produced by USGS on behalf of the Water Resources Program of the Yakama Nation.
Beginning the afternoon of October 22, 2015, a swarm of mostly small earthquakes occurred about 10 km (6 miles) NW of the towns of Crescent and Gilchrist, Oregon. Through the morning of October 23, the Pacific Northwest Seismic Network (PNSN) located 29 events (maximum magnitude M 2.6) and a number of additional events are too small to locate. The PNSN locations are spread out over a 5 by 10 km (3 by 6 miles) area in the vicinity of Ringo and Cryder Buttes, with depths ranging from 1 to 15 km (0.6 to 9 miles). Since the nearest network station is about 40 km (25 miles) to the northeast, location and depth determinations have a high degree of uncertainty and it is quite possible that events are occurring over a much smaller area.
This area has experienced periods of elevated seismicity in the past. In June-August 2001, the PNSN located 6 events (maximum magnitude M 2.6), and in July-August 2012 the PNSN located 20 events (maximum magnitude M 1.1). Prior to the expansion of the Newberry seismic network in 2012 earthquakes were much harder to detect and locate in central Oregon in general and in this area in particular, so it is conceivable that other Crescent-area swarms could have occurred prior to 2012 that were not detected by CVO or the PNSN.
On October 10, intense rain at Mount St. Helens eroded volcanic deposits on the southwest flank of the volcano above Butte Camp dome. Field observations revealed unmistakable tracks of recent debris flows that started in two separate channels some distance above the Loowit 216 trail, and continued as a debris flow at least as far as the Toutle 238 trail crossing. By the time runout reached and merged with the clear-running Kalama Springs discharge, it was all fine material that was easily suspended in the flow and transported far downstream into the Kalama River. Similar debris flow run-outs may have entered the Kalama through another tributary channel. Because the source material for this debris flow consisted of creamy white volcanic deposits, it imparted an unusually light color to the river. With time, the river color will change as the sediment settles out of the water. Additional analysis is underway to better define source material.
Read more about Hydrologic Monitoring at Mount St. Helens on our webpage.
Scientists, civil authorities, and emergency managers from Chile and the U.S. met in California to discuss the challenges of effective volcanic hazard education, response planning, hazard mitigation, and risk reduction, as part of the second Binational Exchange program for Volcanic Risk Reduction in the Americas.
The program focused on the Long Valley volcanic region (California, USA) and Chaiten Volcano (Region de los Lagos, Chile). Both of these restless volcanic systems have erupted rhyolite lava. Eruptions of rhyolite lava exhibit extremely diverse behavior, from sluggish lava flows to catastrophic explosions. The similarities in the nature of the hazards posed at Long Valley and Chaiten and the challenges of communicating with at-risk communities provide opportunities for scientists and civil authorities to learn from one another and strengthen risk reduction in their home countries. In the U.S. and Chile, participants inspected volcano monitoring networks, learned about the geologic history of volcanoes, volcanic hazards, eruption forecasting, disaster preparedness, and communications with affected communities.
The principle coordinators of the Chile-USA exchange are Dr. Margaret Mangan, Scientist-in-Charge of the USGS-California Volcano Observatory in Menlo Park, California, and Dr. Luis Lara, the Head of the Volcano Hazards Program at Servicio Nacional de Geologia y Mineria in Santiago, Chile. The program is funded by the U.S. Agency for International Development/Office of Foreign Disaster Assistance with cooperation from the USGS' Volcano Disaster Assistance Program.
Seismic monitoring equipment on Mount Hood detected small debris flows on the White River over the past several weeks. No significant damage has been reported, but it may have made the Timberline Trail crossing over the White River temporarily more difficult.
The seismic signals of the debris flow rumbling down channel were best recorded by monitoring station PALM, located next to the Palmer chairlift in the Timberline Ski Area. Although the station has a lot of cultural noise, especially during chair lift operations, the debris flow signals are clearly visible. The signals in the spectrograms have gradual onsets, relatively high frequency content (5-10 Hz), and extended durations.
USGS-Cascades Volcano Observatory geologists working in the area on August 21 observed higher sediment-laden stream flows and broad areas adjacent to channels that had recently been inundated by mud and gravel.
Small debris-flow events are not uncommon in the upper reaches of the White River, particularly during periods of extended warm weather or intense rainfall. In this case, meltwater apparently released from the terminus of the White River Glacier, mixed with loose sediment as it traveled down steep narrow channels to create debris flows.
As a reminder to visitors in the area, if you are in a narrow river channel and you feel ground shaking, hear prolonged rumbling, or see a rapidly rising river level, move to the safety of higher ground.
As of August 9, 2015, Dr. Seth Moran takes over the leadership of USGS-Cascades Volcano Observatory from John Ewert, who served as the scientist-in-charge for the past five years.
Seth Moran began his USGS career as a research seismologist for the Alaska Volcano Observatory in 1997. In 2003, Moran joined the staff of CVO as the principal USGS seismologist responsible for studying and monitoring Cascade volcanoes. Seth's timing was fortuitous - in the fall of 2004 Mount St. Helens reawakened after 18 years of quiet. As is typical in all eruption responses, Seth assumed many different roles during the response: conducting his own seismic analyses, coordinating research by others outside CVO, being interviewed by the news media, assembling statements for the news media and working with partner agencies in emergency response.
In addition to Mount St. Helens, a significant percentage of Seth's time has been spent maintaining and improving seismic monitoring capabilities at other Cascade volcanoes, such as installing new seismic stations at Mount Rainier National Park, and developing a new network of eight seismic stations at Newberry Volcano in 2011. Seth has also been active in the larger scientific community being a critical player in the Imaging Magma Under St. Helens experiment, known as iMUSH, jointly funded by the National Science Foundation and USGS to produce a better "picture" of the magma "plumbing system" under the volcano.
John Ewert will rotate back to a staff position at CVO with Volcano Disaster Assistance Program focusing on novel approaches to eruption forecasting and updating National Volcano Warning System documents.
On August 13, a series of small debris flows rumbled down Tahoma Creek, in Mount Rainier National Park. No one was injured and damage was limited to the stream channel inside the Park.
Observations and photos taken by National Park Service geologists during an overflight in the afternoon indicate that the debris flows appear to have started at the terminus of South Tahoma Glacier. Some sediment from the debris flow was visible 8 miles downstream at the Highway 706 crossing.
Looking at seismic data from the Pacific Northwest Seismic Network, the vibrations from the debris flow are recorded on seismograms from Rainier station RER, located at Emerald Ridge overlooking Tahoma Creek. The debris flow signal starts at ~9:50 AM PDT. Signals are emergent, pulsatory, and relatively high-frequency, all characteristics of debris flows. There was a period of time from ~9:50 AM through to ~12:45 PM where signals were occurring relatively continuously, with several tens-of-minutes-long higher-amplitude bursts at 10:15-11:10, 11:25-11:50, and 12:30-12:40 that probably correspond to major debris-flow pulses. No debris-flow-like signals showed up overnight.
This event is similar to numerous debris flows that have occurred at Mount Rainier in past decades. Water stored in the glacier was released and quickly gathered up loose mud, sand, soil, and rock to form a debris flow. Small flows are common at Mount Rainier during late summer and early fall; a second group of debris flows commonly develops from torrential rainfall during early winter storms. Between 1985 and now, more than 30 debris flows have rushed down the Tahoma Creek valley.
The visiting public is reminded to stay clear of valley floors during debris flows and to the safety of higher ground when a debris flow is passing.
The May 18, 1980, eruption of Mount St. Helens included a debris avalanche, lateral blast, pyroclastic flows, lahars, and tephra falls, all of which dramatically altered the drainage basins on the volcano. Since the eruption, scientists have been conducting repeat stream channel cross-section surveys to monitor the response of these channels, as part of a long-term hydrologic monitoring project managed by the U.S. Geological Survey. These data are now available in a new online database that contains 243 survey lines, representing ~100 km of topography, collected over more than 30 years. Cross sections are located within two primary drainage basins—the Toutle River on the north and west flanks of the volcano and the Lewis River on the south and east flanks. The dynamic nature of the database will accommodate the addition of future surveys and data revisions as appropriate. Download the Digital database of channel cross-section surveys, Mount St. Helens, Washington, to see more.
Oregon's Newberry Volcano is the largest volcano in the Cascade Range and covers an area the size of Rhode Island (about 3100 km2 or 1200 mi2). Unlike familiar cone-shaped Cascade volcanoes, Newberry was built into the shape of a broad shield by repeated eruptions of mostly fluid lava over the past 400,000 years. Between the lava-producing eruptions the volcano has erupted explosively. The most recent eruption, about 1,300 years ago, was explosive and ended with the extrusion of the Big Obsidian Flow within the volcanic caldera. This new poster of Newberry Volcano uses LiDAR (light detection and ranging) technology to reveal previously unseen detail in the volcano's youngest lava flows and vents—the Lava Butte cinder cone, Newberry's northwest rift zone, Central Pumice Cone and The Big Obsidian Flow. Download the poster Newberry Volcano's Youngest Lava Flows to see more.
Crews from the USGS-Cascades Volcano Observatory return from working with the Alaska Volcano Observatory, Plate Boundary Observatory, and IRIS' Transportable Array to repair, refurbish and rebuild volcano monitoring stations in Alaska, including the installation of a new volcanic gas monitoring site at the summit of Augustine. The station is similar to the SNIF monitoring station that currently operates in the crater of Mount St. Helens. Visit the Alaska Volcano Observatory to see volcano updates and recent images of fieldwork. Read about volcanic gas monitoring at Mount St. Helens and view a month's worth of monitoring data by clicking on Mount St. Helens Monitoring and zooming into the crater to find station SNIF on the interactive map.
Research geologist Carl Thornber leads a group of Mount St. Helens National Volcanic Monument interpretive rangers and volunteers along the boardwalk at the Trail of Two Forests, explaining the formation of lava tubes and tree molds. The longest lava flow at Mount St. Helens is the 1900-year-old Cave Basalt Flow, erupted from a vent on the south flank of the volcano which traveled 11 km (~7 miles) downslope to the Lewis River. Many flow features are still visible including the Ape Cave lava tube. This pahoehoe flow is similar in composition, size and physical character to tube-fed lava flows that are currently active at KÄ"lauea Volcano, Hawaii. Plan a visit to the Ape Cave Interpretive Site to learn more about the Pre-1980 Eruptive History of Mount St. Helens, Washington. Visit the Hawaii Volcano Observatory for images and information about KÄ"lauea.
USGS-CVO is using airborne lidar data to develop Digital Elevation Models (DEMs) for the Mount St. Helens area. DEMs are a useful tool for monitoring natural hazards, studying volcanic landforms and tracking changes in fluvial and glacial geomorphology. The DEMs were created from lidar data collected in 2007 and 2009, and are available for download in 1- and 10-m resolutions, and as a 1-m hillshade. These geospatial data files require geographic information system (GIS) software for viewing.
The Mount Baker-Snoqualmie National Forest is accepting comments on a USGS–CVO proposal to install four volcano monitoring stations at Glacier Peak. Glacier Peak is a potentially active volcano posing mudflow, ash fall, landslide, flood and earthquake hazards to nearby communities and metropolitan areas downstream. With only one seismometer currently operating, there is a need for more robust monitoring to accurately detect the early signs of volcanic unrest.
The four collocated seismic and GPS stations include electronic monitoring equipment, antenna, batteries and solar panels mounted to an equipment enclosure. Additional information on this project, the Scoping Letter and how to comment is available from the Mount Baker-Snoqualmie National Forest, Glacier Peak Monitoring Stations. Comments are due June 20, 2015. Follow this link for more information on Glacier Peak, its history and hazards.
During May 2015, the Washington Emergency Management Division, Pierce County Department of Emergency Management, USGS-Cascades Volcano Observatory, and other emergency management agencies are coordinating events for Volcano Preparedness Month. Residents are encouraged to become familiar with volcano risk within their communities and to take steps that reduce potential effects on people and property. Informative talks by USGS-CVO scientists are planned:
May 18 marks the 35th anniversary of the catastrophic eruption of Mount St. Helens. The eruption remains a seminal historical event; studying it and its aftermath revolutionized the way scientists approach the field of volcanology. Special events are planned at the Johnston Ridge Observatory and Coldwater Science and Learning Center from May 16-18.
In April and May, bring scientists into your classroom with Volcano Explorers, live, interactive video presentations by preeminent scientists and educators. The presentations are aimed at 5th – 8th grade classes that study earth history, landforms or geologic processes. Using webinar technology, Volcano Explorers easily works in nearly any classroom with a computer, projector and internet connection. Visit the Volcano Explorers web for more information.
The Mount Hood National Forest is accepting comments on a USGS–CVO proposal to install four volcano monitoring stations on the upper flanks of Mount Hood. The unmanned remote monitoring stations would be located in the Wilderness area, occupying a total of 105 square feet of land. The stations would be constructed with minimal impact on the environment and located away from trails.
While not erupting, Mount Hood shows signs that it is a functioning, active volcano. Mount Hood produces frequent earthquakes, and steam and volcanic gases are emitted in the area around Crater Rock near the summit. The USGS designated Mount Hood as a very high threat volcano in its 2005 National volcanic threat assessment due of the volcano's eruptive history, current activity and proximity to communities and infrastructure downstream and downwind. These proposed stations greatly enhance the ability of USGS–CVO to detect subtle geophysical signals beneath the volcano and determine with greater confidence whether or not the volcano poses any imminent threat of eruption. Additional information on this project and how to comment is available from the Mount Hood National Forest. Follow the links for more information on the Mount Hood volcano and the proposed monitoring stations.
Applications are being accepted for a five-day geology and technology field camp for middle school girls at Mount St. Helens. GeoGirls will explore the volcano, work with scientists, do hands-on experiments and create a short video and website about their week to share with family and friends. Applications are accepted now until May 20. Visit the Mount St. Helens Science and Learning Center GeoGirls web page for more information on the application process.
The USGS-Cascades Volcano Observatory opens its doors to the public on Saturday, May 2, for a one-day open house. Scientists will be on-hand from 10:00 am to 5:00 pm to share the results of their research and talk about volcano hazards. Hands-on activities and equipment demonstrations will be featured. Download the flyer to share others – .
The 1980 activity of Mount St. Helens began on March 20 with an intensifying swarm of earthquakes. The first steam-blast eruption occurred a week later, with high levels of seismic activity, formation of a summit crater, and deformation of the north flank of the volcano. This continued up to the climactic eruption on the morning of May 18. Follow the USGS scientists as the events unfolded in 1980, with daily posts about volcanic activity, pictures, and video on the USGS Volcanoes Facebook page.
Mount St. Helens' summit slid away on a sunny morning May 18, 1980, unleashing a powerful landslide and blast that flattened miles of forest, flooded valleys and sent an ash cloud high into the sky; 57 people were killed. Soon after the eruption, USGS–Cascades Volcano Observatory scientist Richard Waitt began interviewing witnesses and survivors. Initially, the project was to help scientists document volcanic phenomena, assess hazards, and learn from the mountain. It soon became clear however, that the stories added unique details to the hard data we scientists were gathering. After more than three decades and hundreds of interviews, these stories are published in Path of Destruction, Eyewitness Chronicles of Mount St. Helens — a new glimpse at a defining cataclysm in the region's history. Read more on Mount St. Helens' eruptive past.
One of the most tragic volcanic events of the 20th century occurred in Colombia, in 1985, when an eruption of Nevado del Ruiz produced lahars that swept down river valleys and destroyed communities in its path. Mount Rainier and other volcanoes of the Pacific Northwest's Cascade Range are similar to Nevado del Ruiz in many respects—massive amounts of snow and ice, a long history of lahars, and narrow valleys leading to populated areas. Could what happened at Nevado del Ruiz happen in the Pacific Northwest? And if it did, are we prepared?
In 2013, the Colombia-US Bi-national Exchange was created to help scientists, emergency managers and first responders in both countries to learn from the events in Colombia and to work toward improving disaster preparedness in communities located near volcanoes. Watch a video about the Colombia-US Bi-national Exchange and learn more about how you can prepare for the next volcanic eruption.
Washington State lahar-hazard zones contain an estimated 191,555 residents, 108,719 employees at 8,807 businesses, 433 public venues that attract visitors, and 354 dependent-care facilities with individuals who will need assistance to evacuate during an emergency. Mount Rainier lahar-hazard zones contain the highest percentage of assets, followed by Mount Baker, Glacier Peak, Mount St. Helens and Mount Adams. Residential populations within lahar-prone areas increased between 1990 and 2010, mainly in the Mount Rainier lahar-hazard zone, with some communities doubling and tripling their at-risk population. Many of these new residents may be unaware of the lahar threat. This study quantifies potentially at-risk populations, to aid emergency managers, local officials, and the public in understanding the hazards and in developing preparedness, mitigation, and recovery plans for affected communities. Read
Variations in community exposure to lahar hazards from multiple volcanoes in Washington State (USA) online. Check the Simplified Hazard Maps to see Cascade Range volcano-hazard zones.
Volcano monitoring equipment, both past and present, is on temporary display at the Washington State History Museum in Tacoma, Washington. The exhibit includes an older model drum-style seismograph and a modern-day "spider," a self-contained instrument package that can be deployed to support data collection efforts on a short-term basis. See the instruments and explore the historic interaction between the people of Washington and its ever-changing volcanic landscape through native legends, scientific discovery, contemporary environmental management, and disaster preparedness. More information on the Living in the Shadows exhibit is at the Washington State History Museum.
The large landslide that occurred on March 22, 2014 near Oso, Washington, was unusually mobile and destructive. Eighteen million tons of sediment slid downslope and crossed the half-mile wide river floodplain in about 1 minute with devastating consequences to the local community. A major focus of USGS researchers has been to understand the landslide's behavior. This published study reveals that the collapsing material compressed already-unstable wet sediment to produce liquefaction and decreased friction, leading to the landslide's high mobility. Numerical simulations indicate that the landslide process at Oso could have unfolded very differently (with much less destruction) if initial conditions had been only subtly different. Understanding of the Oso event adds to the knowledge base that can be used to improve future landslide hazard evaluations.
Read Landslide mobility and hazards: implications of the 2014 Oso disaster and watch the computer simulations online.
Falling ash, even in low concentrations, can disrupt human activities hundreds of miles downwind of a volcano, and drifting clouds of fine ash can endanger jet aircraft thousands of miles away. The economic effects of airborne volcanic ash were demonstrated during the 2010 eruption of EyjafjallajÃ¶kull volcano in Iceland, when flight cancellations and delays throughout Europe caused billions of dollars in economic loss to airlines and travelers. The most effective way to reduce risk from dispersed volcanic ash is to forecast where it will go and what areas it will affect. A computer model called Ash3d uses current wind speed and directional data along with eruption characteristics to plot the potential path of an ash cloud. See today's computer simulations for hypothetical eruptions at Mount St. Helens and read more about Ash3d.
Scientists from CVO and the Istituto Nazionale di Geofisica e Vulcanologia (Italy) are taking advantage of advances in technology to design and construct lightweight, portable, power-conserving volcanic gas monitoring equipment. The instrument (active long-path differential optical absorption spectroscopy or LP-DOAS) uses novel fiber-coupling and ultraviolet LED technology to send a beam of ultraviolet or visible light to a reflector located tens to hundreds of meters away. Characteristic absorption lines of trace gases present in the light path are measured in the spectrum of returning light. The robust design and versatility of the instrument make it a promising tool for monitoring of volcanic degassing and understanding processes in a range of volcanic systems. Read the abstract Development of a portable active long-path differential optical absorption spectroscopy system for volcanic gas measurements.
Staggering losses from widely publicized lahar-related disasters at Mount St. Helens, Nevado del Ruiz (Colombia), Mount Pinatubo (Philippines) and Mount Ruapehu (New Zealand) have demonstrated how lahars significantly threaten the safety, economic well-being and resources of communities downstream of volcanoes.
In response, communities have designed, engineered, and constructed protective structures, diversion channels and containment basins, sometimes with limited effect. The most effective risk-reduction strategy may be to have a public that is well informed about the nature of hazards to their community, informed about how to lessen their risks, and are motivated to take risk-reducing actions.
Scientists play a critical role in risk mitigation. By informing officials and the public about realistic hazard probabilities and scenarios, helping to evaluate the effectiveness of proposed risk-reduction strategies, promoting acceptance of (and confidence in) hazards information, and communicating with emergency managers during extreme events, communities are better able to prepare for and recover from damaging events.
This paper reviews a number of methods for lahar-hazard risk reduction, examines the limitations and tradeoffs, and provides real-world examples of their application in the U.S. Pacific Northwest and in other volcanic regions of the world.
Read Reducing risk from lahar hazards: concepts, case studies, and roles for scientists.
In late spring or early summer of 2012, a flood originated at a small moraine-dammed lake on Three Finger Jack volcano in the Mount Jefferson Wilderness. Channel erosion or slope collapse breached a natural dam, draining half the lake volume. The resulting debris flow formed a bouldery deposit for about a quarter mile (0.35 km) downslope. As Cascade Range alpine glaciers shrink in size and average annual temperatures rise, lakes have formed in deglaciated areas. Those dammed by unconsolidated moraines are susceptible to breaching and pose flooding hazard downstream. Read about the event, Debris flow from 2012 failure of moraine-dammed lake, Three Fingered Jack volcano, Mount Jefferson Wilderness, Oregon.
The digital database for the Geologic Map of Upper Eocene to Holocene Volcanic and Related Rocks in the Cascade Range, Washington, is now available online. This geospatial database is one of a series of maps that shows Cascade Range geology by fitting published and unpublished mapping into a province-wide scheme of lithostratigraphic units. Geologic maps of the Eocene to Holocene Cascade Range in California (in progress) and Oregon complete the series, providing a comprehensive geologic map of the entire Cascade Range that incorporates modern field studies and that has a unified and internally consistent explanation. The complete series will be useful for regional studies of volcanic hazards, volcanology, and tectonics.
Debris flows are water-saturated masses of soil and fragmented rock that can rush down mountainsides, funnel into stream channels and inundate valley floors downstream. These flows can be devastating to people and property. In a recent documentary, NOVA explores events before, during and after the March 22, 2014, landslide near Oso, Washington as well as other landslides from around the world, to find out why these events occur and what can be done to mitigate the hazards. View the program, Killer Landslides, online.
Watch what happens when scientists conduct their own debris flow experiments at the USGS debris-flow flume.
During the May 18, 1980, eruption of Mount St. Helens, approximately 2.5 billion cubic meters (3.3 billion cubic yards) of material was deposited in the upper North Fork Toutle River valley. Thirty-four years later, excess sediment continues to wash down the river at a rate of 3 million tons per year, increasing flood risk for local communities and impacting river navigation and migrating fish. Researchers have been looking into ways in which innovation and technology can be used to improve methods of tracking sediment movement in real-time. Results of a new study show that turbidity, or a measure of how cloudy the water is, can be used as a surrogate to quickly estimate suspended-sediment concentration in a highly disturbed river system. The method is promising, providing insight into how the Mount St. Helens sediment-source terrain and depositional areas evolve over time, and in managing excess sedimentation in the lower Toutle River basin. Read Correlations of Turbidity to Suspended-Sediment Concentration in the Toutle River Basin, near Mount St. Helens, Washington, 2010–11.
In the past, drum recorders were used to display seismograms on pieces of paper. These mechanical records have largely been replaced by computers, which digitize the data and store it in digital form. The digital data can be displayed in a variety of ways by a computer, such as a webicorder plot. This webicorder video provides a tutorial for anyone interested in interpreting the seismic records on public webicorder displays.
In the early morning hours of September 23, 2004, a swarm of small-magnitude earthquakes about half a mile below Earth's surface marked the reawakening of Mount St. Helens. On October 1, 2004, the first of several small explosions shot a plume of volcanic ash and gases skyward. A growing welt beneath Crater Glacier heralded the rise of semi-solid magma that erupted onto the surface, forming rocky spines, smooth-sided ridges, and jumbled piles of lava over the next 34 months. During the eruption, scientists made important strides in volcano monitoring, developing new tools for investigation and insight into eruptive behavior.
View the 2004-2008 Mount St. Helens Eruption video and read about the eruption in the 2004-2008 event timeline and statistics.
Since 2008, the Mount St. Helens Institute has brought live, interactive video presentations to students across the country. This fall, CVO scientists are featured:
USGS-CVO scientist Christoph Kern is co-author on a study that used ultraviolet spectral satellite data to quantify the exceptionally high sulfur dioxide (SO2) emissions from KÄ"lauea Volcano during the 2008 opening of the summit Overlook Crater. KÄ"lauea is particularly suited for quantitative investigations from satellite observations due to the large SO2 emission rates, absence of interfering gas emission sources, the clearly defined downwind plumes caused by steady trade winds and the generally low cloud cover downwind. This allowed the application of a new methodology in which monthly mean SO2 emission rates and effective SO2 lifetimes were derived simultaneously from the observed mean downwind plume evolution. Read Estimating the volcanic emission rate and atmospheric lifetime of SO2 from space: a case study for KÄ"lauea volcano, Hawai`i.
This summer, a new monitoring station was installed on the lava dome in the crater of Mount St. Helens to "sniff" volcanic gases. Like most volcanoes, the majority of the gas emitted at Mount St. Helens is water vapor (H2O) and carbon dioxide (CO2) with lesser amounts of sulfur dioxide (SO2) and hydrogen sulfide (H2S). In the past, scientists would visit sites inside the crater or conduct airborne surveys to collect gas emission data. With this new station, gas concentrations can be measured daily and the monitoring data sent back to the Cascades Volcano Observatory via radio link for analysis. Monitoring the chemical composition of these gases offers important clues to the inner workings of the volcano. An increase in gas output or a change in the ratios of the different gases can be some of the first above-ground signs of an increase or important change in volcanic activity. Read more about
volcanic gas monitoring at Mount St. Helens.
Debris flows are water-saturated masses of soil and fragmented rock that can rush down mountainsides, funnel into stream channels and form lobate deposits when they spill onto valley floors. These flows can be devastating to people and property. To understand the variables that contribute to debris flows, scientists use numerical models to test hypotheses about how flows begin and move, and compare the results to real-world examples and physical experiments.
A new approach to debris-flow modelling focuses on the impact of pore pressure within the flow and how it changes flow characteristics. Flow motion can be triggered in several ways, by gradually increasing pore pressure (simulating the effect of rainfall or snowmelt infiltration), gradually reducing the basal friction angle (simulating the effects of rock weathering or decay of roots that help bind soil), gradually changing the slope geometry (simulating erosion or human intervention), or rapidly changing the force of gravity (simulating earthquakes). What happens next depends on pore-pressure feedback that accompanies the expansion or contraction of the material as it moves. For loosely packed sediment, slope failure can lead to positive pore-pressure feedback, making partial liquefaction and runaway debris-flow motion almost inevitable. Alternatively, densely packed sediment with negative pore-pressure feedback may lead to slow or intermittent landslide motion, although it does not preclude debris-flow initiation.
This new depth-averaged numerical model allows feedbacks to develop as the simulation unfolds, to demonstrate that the evolving debris dilation rate, coupled to the evolution of pore-fluid pressure, plays a primary role in regulating debris-flow dynamics. The model helps to explain high mobility exhibited by many large debris flows. Read the two abstracts online: A depth-averaged debris-flow model that includes the effects of evolving dilatancy. I. Physical basis and A depth-averaged debris-flow model that includes the effects of evolving dilatancy. II. Numerical predictions and experimental tests. Also, watch videos of experiments at the USGS debris-flow flume.
The Condit Dam was a hydroelectric facility constructed in 1912–1913 on the White Salmon River, Washington. Over its nearly 100-year existence, the dam trapped sand, silt, and clay that washed down from the southern Washington Cascade Range, including Mount Adams. The dam was breached in late 2011 and removed to restore fish passage to upstream spawning grounds.
Cameras were set-up to capture erosion of reservoir sediment following breaching and measurements of suspended sediments were made at stations downstream for a 15-week period. Upon opening the outlet tunnel at the base of the dam, the impounded Northwestern Lake drained within 90 minutes. As reservoir erosion proceeded, sediment concentration increased and flow became hyperconcentrated, at first noisy and turbulent but then quiet and viscous. Within 24 hours, 20% of the sediment stored behind the dam washed downstream. In the days and weeks after the breach, erosion and transport of sediments slowed. The channel evolved, lowering to near its original elevation at a gauge site within 15 days of breaching.
The study of the geomorphic response to dam removal was an opportunity to observe erosion processes and the downstream behavior of released sediment. New insights may be applied to the understanding of other disturbances that inject substantial sediment volumes into rivers such as volcanic eruptions, landslides, or when floods entrain great volumes of channel sediment. Read Rapid reservoir erosion, hyperconcentrated flow, and downstream deposition triggered by breaching of 38-m-tall Condit Dam, White Salmon River, Washington.
USGS and its partners invite educators to join us for a fun and informative teacher workshop at Mount Rainier National Park. This five-day classroom and field-based workshop offers science information, hands-on classroom activities, and resources that will enrich your understanding of Cascade volcanoes and aid in your ability to teach about volcanoes in your classroom and on class field trips. Credits and clock hours are available.
Visit the Mount Rainier Teacher Professional Development webpage to register; download the Mount Rainier Teacher Training flyer to share with colleagues.
Explosive eruptions are awesome displays of nature's power that dramatically alter landscapes downwind or downstream of a volcano. Vegetation is damaged, topography may be changed, and large volumes of fragmental material are deposited on hillsides, valley floors and into streams.
While explosive eruptions are hazardous in their own right, the stream drainages responding and adjusting to such volcanic disturbances can pose additional hazards on downstream communities up to 60 miles (100 km) or more from a volcano. Affected drainage basins typically exhibit higher rates and volumes of precipitation runoff, and sediment erosion and transport, than in similar unaffected basins. Recovery of disturbed fluvial systems takes decades to centuries to reach a stable geomorphic state. Read more in Hydrogeomorphic effects of explosive volcanic eruptions on drainage basins.
A monitoring spider is now on display at the Coldwater Science and Learning Center at Mount St. Helens. Visitors have an opportunity to see the instrument up-close and learn more about how it is used to monitor eruptive activity inside the crater.
The spider was engineered and deployed during the 2004-2008 eruption of Mount St. Helens to detect and triangulate shallow earthquakes, monitor local ground deformation and uplift, detect lightning that might indicate an ash eruption and low frequency sound from explosions. The spider embodies the ability of people to find new ways to solve problems and design instrumentation that increases our understanding of volcanic eruptions.
The Coldwater Science and Learning Center is open Saturday and Sunday from 10 am to 6 pm. The Center can also be reserved for schools, education and science groups interested in taking field trips and doing research at Mount St. Helens. Contact Grace Schmidt at the Mount St. Helens Institute for reservations. View information about the Center at Mount St. Helens National Volcanic Monument.
InSAR (Interferometric Synthetic Aperture Radar) is a technique for mapping subtle ground deformation using radar images from Earth-orbiting satellites. With its global coverage and all-weather imaging capability, InSAR has become an increasingly important technique for studying volcanoes in remote regions such as the Aleutian Islands.
For a new book, InSAR Imaging of Aleutian Volcanoes - Monitoring a Volcanic Arc from Space, USGS scientists processed nearly 12,000 SAR images to produce about 25,000 interferograms for 52 Aleutian volcanoes that have been active during historical time. During the 20-year study period, InSAR detected some form of deformation at more than 80% of the 44 volcanoes with adequate InSAR coverage.
The spatial distribution of deformation data from InSAR, combined with other monitoring data and eruption information, helps scientists to link changes on the surface to processes occurring beneath the volcano. View details at InSAR Imaging of Aleutian Volcanoes: Monitoring a Volcanic Arc from Space, read more at Monitoring Ground Deformation from Space.
May 18 marks the 34th anniversary of the catastrophic eruption of Mount St. Helens. The eruption remains a seminal historical event; studying it and its aftermath revolutionized the way scientists approach the field of volcanology. Not only was the eruption spectacular, it occurred in daytime, at an accessible volcano, in a country with the resources to transform disaster into scientific opportunity, amid a transformation in digital technology. Lives lost and the impact of the eruption on people and infrastructure downstream and downwind made it imperative for scientists to investigate events and work with communities to lessen losses from future eruptions. Follow the signs and symptoms of volcanic unrest that led to the May 18, 1980 eruption in the volcano activity update archives. Sign up with the Volcano Notification Service to receive news of current activity.
Lahars (volcanic debris flows) are a hazard at many of the world's volcanoes. Consisting primarily of water, mud and rock debris with a consistency often compared to wet concrete, lahars surge down steep volcano flanks into and along river channels tens, to a hundred or more miles (kilometers) downstream, destroying property and claiming lives. The Laharz desktop software helps users plot areas of potential inundation by lahars, debris flows and rock avalanches, using a digital elevation model for a base, and user-set parameters for the lahar initiation location(s) and volume(s). The result shows the extent of inundation in connected stream drainages and areas downstream. The impacted areas can be combined using a geographic information system (GIS) with other types of volcano hazard information, local infrastructure, hydrology, population, and contours or shaded relief to produce volcano hazard-zonation maps, expanding the ability of communities to understand hazards and mitigate the effects of future volcanic eruptions. Open-File Report 2014-1073 contains an explanation of how to install and use the software (Laharz_py) and a sample data set for Mount Rainier, Washington.
During the month of May, residents are encouraged to take the necessary steps to find out about volcanic hazards where they live, work and play, and how to survive and recover from the next eruption.
Slowly emerging patterns of behavior at Mount St. Helens are giving scientists at the USGS-Cascades Volcano Observatory and the Pacific Northwest Seismic Network new insights into activity beneath the volcano. Since the end of the 2004-2008 dome-building eruption, scientists have been monitoring subtle inflation of the ground surface and minor earthquake activity that is reminiscent of that seen in the years prior to the 2004-2008 eruption.
Careful analysis of these two lines of evidence now gives us confidence to say that the magma reservoir beneath Mount St. Helens has been slowly re-pressurizing since 2008. It is likely that re-pressurization is caused by arrival of a small amount of additional magma 4-8 km (2.5-5 miles) beneath the surface. This is to be expected while Mount St. Helens is in an active period, as it has been since 1980, and it does not indicate that the volcano is likely to erupt anytime soon. Re-pressurization of a volcano's magma reservoir is commonly observed at other volcanoes that have erupted recently, and it can continue for many years without an eruption.
To learn more, field work this summer will include measuring the types and amounts of gases being released, and the strength of the gravity field at the volcano. The information collected at Mount St. Helens continues to help scientists analyze behaviors here and at other volcanoes and to improve eruption forecasting capabilities. View the full and read the . Sign up for the Volcano Notification Service to receive your own updates about volcanic activity at Mount St. Helens or other volcanoes. Read more about Monitoring Mount St. Helens online.
CVO staff and sediment specialists from USGS offices around the country led the Sediment Data Collection Techniques training course in Castle Rock, Washington. The week-long course was attended by 30 students representing the USGS, U.S. Army Corps of Engineers, U.S. Bureau of Reclamation, and the Nooksack and Klamath Tribes. The course provided participants with an understanding of basic fluvial-sediment concepts, sediment sampler characteristics, sampling protocol and techniques, laboratory analysis, surrogate technologies, and quality-assurance procedures. Field training exercises on the Cowlitz and North Fork Toutle Rivers gave students valuable hands-on experiences. Erosion of 1980 deposits at Mount St. Helens resulted in higher sediment loads in the Toutle and lower Cowlitz Rivers, decreasing the carrying capacity of channels, increasing flood risk, and affecting aquatic habitats. Sampling is a method of tracking the movement and volume of material moving downstream. For more information, see USGS Surface Water Information -- Fluvial Sediment, and Hazards from Post-Eruption Excess Sediment at Mount St. Helens.
Over the past half-century, great advances have been made in understanding debris flow behavior. Studies find that most debris flows originate on slopes that are steeper than 25 to 30 degrees and are mantled with low-cohesion soils and/or fragmented rocks that have become at least partially saturated by water. The resulting downslope flow can scour and erode a channel with devastating consequences for communities in its path. This new article describes the debris flow process from initiation to end, and provides guidance for assessing debris flow hazards. Read more at Debris flows: behaviour and hazard assessment.
An episode of strong seismic tremor (a continuous release of seismic energy) occurred during the build-up to the 2004-2008 eruption of Mount St. Helens. This episode was remarkable because no explosion or eruption immediately followed. Research found that in this case, the tremor occurred as gas-poor magma under Mount St. Helens was slowly forced upward for about 49 minutes, breaking and tearing the fabric of the rough conduit walls. The seismic waves produced by this movement resonated within the conduit to form hybrid waves that were recorded in far-field seismic stations as tremor. The conduit resonance masked the source of the tremor, making it difficult to determine if the tremor was leading to an explosion. An understanding of the different ways tremor can be generated requires that information from other sources, such as visual observations, deformation, geology and gas geochemistry, be used in order to interpret events that could lead to an eruption. Read more at Volcanic tremor masks its seismogenic source: Results from a study of non-eruptive tremor recorded at Mount St. Helens, Washington.
Around 170,000 years ago, explosive volcanic eruptions near Bend, Oregon, produced gravity-driven currents of hot volcanic gas and pyroclastic rocks. When the flows stopped moving, they were hot enough to weld together. This new study examines changes in permeability and porosity during welding, helping to understand how the deposits initially formed and how fluids, such as groundwater, flow through volcanic tuffs. Read Compaction and gas loss in welded pyroclastic deposits as revealed by porosity, permeability, and electrical conductivity measurements of the Shevlin Park Tuff.
It has been a busy year for the USGS Volcano Science Center, as shown in this sample of our favorite 2013 images: three volcanoes in Alaska erupted for several weeks each, KÄ"lauea Volcano in Hawaii continued its 31-year long eruption, Pagan Volcano in the Commonwealth of the Northern Mariana Islands showed persistent low-level activity, and several Cascades volcanoes, as well as the Yellowstone and Long Valley calderas, demonstrated their active status with small swarms of earthquakes. Detailed data analyses over this past year continue to increase our understanding of volcanoes and collaboration among geoscientists and hazard planners, both nationally and internationally, drew attention to volcanic hazards and the need for continued monitoring and community preparation for future eruptions. View the USGS Volcano Science Center Images and Events from 2013 online.
The southernmost Lake Natron basin is located along the East African rift zone in northern Tanzania. It is here where Oldonyo Lengai, Tanzania's most active volcano of the past several thousand years, built its edifice. Oldonyo Lengai's eruptions are chiefly explosive, producing tephra fall, pyroclastic flows, and lahars; its history includes periodic collapse of the volcano's flanks and deposition of volcanic debris-avalanche deposits across the southern basin floor. A cooperative venture among USGS and coauthors from the Geological Survey of Tanzania and the University of Dar es Salaam, produced this geologic map of the area including new radiometric ages and geochemical analyses. View the Geologic map of Oldonyo Lengai (Oldoinyo Lengai) volcano and surroundings, Arusha Region, United Republic of Tanzania: U.S. Geological Survey Open-File Report 2013-1306 and read the accompanying pamphlet.
A photo assistant with The Columbian (Vancouver, WA) recently discovered unprocessed black-and-white film taken by staff photographer Reid Blackburn in April, 1980. The images show a restless Mount St. Helens five weeks before the catastrophic May 18 eruption that took Mr. Blackburn's life and the lives of 56 others. Read about the discovery in Photographer's parting shots of Mount St. Helens and view footage of the eruption on the Mount St. Helens Multimedia page.
This season's first lake-ice quakes are occurring at Newberry Volcano. Aided by record-setting subfreezing temperatures, the popping and cracking of ice in the caldera's lakes is picked up by local seismic stations. The lake-ice quakes do not resemble standard volcanic low-frequency or high-frequency events and are sporadically observed in the winter at ice-covered lakes in Yellowstone, Long Valley, and elsewhere. Ice quakes were first noticed at Newberry in December 2011, after the new seismic network was installed. The sensitive network was designed to detect earthquakes and other seismicity that occur beneath the Newberry Volcano and has also provided insight into the way sound travels through the upper crust in the area. Visit the Newberry webpage to learn more about this volcano.
On September 28, after about 10 hours of steady rain, an acoustic flow monitor (AFM) on the South Fork Toutle River recorded the passage of small debris flows. The AFM showed significantly elevated signals for about three hours as water, mud and rock rolled downstream in small surges. During recent field work, crews visited the area to see the evidence -- remnant debris flow surfaces on channel margins, new deposits, mud lines and bent, scoured alders. The flow likely traveled for over a mile downstream of the AFM location. No damage to infrastructure was reported. Read more about sediment erosion, transportation and deposition at Hydrologic Monitoring at Mount St.Helens.
This newly published Scientific Investigation Map (SIM) highlights the geologic history and structural features of the westernmost portion of the Columbia River Gorge, and areas in Clark and Multnomah Counties. The SIM shows 27 million year-old Elkhorn Mountain lava flows, Columbia River basalts, and vents of the Boring Volcanic Field. SIM 3257 describes how the area was profoundly affected by glacier-outbursts from Glacial Lake Missoula and the ancestral Columbia and Sandy Rivers, furthering our understanding of the history and hazards of the environment in which we live. View the Geologic Map of the Washougal Quadrangle, Clark County, Washington, and Multnomah County, Oregon and explore other Scientific Investigation Maps for nearby Clark and Cowlitz Counties (Washington), Columbia and Multnomah Counties (Oregon), Mount St. Helens, Three Sisters, Mount Mazama, Lassen and Medicine Lake.
Forty conferees from the 2013 National Science Teachers Association meeting in Portland, Oregon, participated in a field trip to CVO to learn about Cascade hazards and volcano monitoring. Teaching about Cascade volcanoes has many benefits--sparking enthusiasm for science and math, helping students to understand the connection between volcanoes and people, students and teachers can help to develop preparedness strategies for their schools and communities, and volcano studies bring opportunities to explore current events in the Pacific Northwest and around the globe. Online resources are available for teaching and learning about local volcanoes in accordance with state standards. See more at Teaching Resources and Website Use in the Classroom.
Question: If you change a single variable in a debris flow, what difference does it make? Answer: Do experiments and find out! New side-by-side videos show what happens when you change the volume or type of material in a debris flow, the characteristics of the bed, and what happens when the flow encounters a corner or wall. The experiments confirm two decades of scientific results and help scientists understand how small changes can affect the behavior of destructive flows. This publication is available only on the web, Video Documentation of Experiments at the USGS Debris-Flow Flume 1992-2006 (amended to include 2007-2013). A description of the area where the experiments were conducted is at Debris-flow flume at H. J. Andrews Experimental Forest, Oregon. Additional interpretations and data from other experiments at the USGS debris-flow flume can be found in other online reports.
Over 200,000 children from over 70 countries will explore natural disasters and what can be done to keep people safe, in the 2013 "Nature's Fury" FIRST LEGO challenge. Researchers interested in focusing on the Cascade volcanoes for this year's challenge have many resources available to them:
This summer, USGS-CVO monitoring stations at Crater Lake, Oregon, were upgraded to send digital signals. The digital stations provide higher quality data and therefore more accurate recordings of seismicity within the caldera. Once installed, the stations are simpler to maintain than analog stations. The monitoring network currently monitors both seismicity and ground deformation in the caldera, created when the 12,000 ft (3,660 m) high Mount Mazama collapsed 7,700 years ago following a large eruption. For more information on volcano monitoring, view Monitoring Cascade Volcanoes.
Last month, CVO scientists participated in a community-wide science, technology, engineering, and math (STEM) festival. The event, held at Clark College, encouraged adults and youth of all ages to participate in hands-on activities, experiments and talks given by experts. STEM-Fest participants had the opportunity to closely examine ash from the 1980 eruption of Mount St. Helens, look at rock samples, see minerals in thin section, conduct an experiment demonstrating ash transport, and talk about the volcanic hazards in their communities. For more information about volcano hazards and simplified maps showing hazard areas, view Volcano Hazards in the Cascade Range.
Colombia suffered one of the worst volcanic disasters of the 20th century in November, 1985, when ice-clad Nevado del Ruiz volcano erupted and communities at its base were destroyed by large lahars (volcanic debris flows). More than 23,000 fatalities occurred in the city of Armero and surrounding communities. The disaster had a profound and constructive effect on scientific and disaster management in Colombia and around the world.
Organized by the USGS-CVO and the Washington Emergency Management Division with support from the USAID's Office of U.S. Foreign Disaster Assistance, scientists, first-responders and emergency/hazard planning officials met in Colombia and again in the Puget Sound area to observe, learn and absorb best practices for preparing for and responding to volcanic crises. Read more at Colombian and US Officials Meet to Save Lives through Exchange, and Colombians Urge Pacific Northwesterners To Appreciate Lahar Danger.
Summer is a busy season for USGS-CVO field crews. When weather permits, monitoring stations are repaired, replaced or fitted with new technologies to improve volcano monitoring. Crews also survey and make direct observations of landforms, such as channels and streams. The information is used to improve our understanding of Mount St. Helens (and other volcanoes) during both eruptive and non-eruptive periods. View images of Mount St. Helens 2013 Summer Fieldwork online.
Scientists from CVO and the Alaska and Hawaii Volcano Observatories installed a novel sulfur dioxide (SO2) camera system at Kilauea's summit caldera. The system uses two ultra-violet cameras to continuously measure the emission rate of SO2 released from the active summit eruption site with imagery streaming in near real-time. This is one of the first camera-based SO2 gas monitoring systems to be installed at a volcano. The high spatial and temporal resolution of the instrument is expected to provide unique insights into degassing processes at Kilauea, with application to other active volcanoes worldwide. For more information, read a recent article on improvements to gas monitoring techniques, Applying UV cameras for SO2 detection to distant or optically thick volcanic plumes.
Ten middle school teachers from around the Pacific Northwest took part in a 5-day classroom/field studies training workshop at Mount Rainier National Park. Led by USGS-CVO and National Park Service educators, participants learned about the tectonic setting of Mount Rainier, how volcanoes work, volcanic hazards and processes, reading the geologic record and preparing for the next eruption in the Cascade Range. The information will be used in classrooms to augment science curriculum and to increase community hazard awareness. Hands-on teaching activities and information about Cascade volcanoes and volcanic processes are available in Living with a Volcano in your Backyard -- An Educator's Guide with Emphasis on Mount Rainier.
Each year, gas samples are collected from the fumaroles on the north side of Mount Hood's Crater Rock and the samples are taken back to the laboratory for an analysis of the gases' chemical composition and concentration. Gas compositions are also measured by analyzing the absorption of sunlight that occurs as it falls through the gas cloud, as pictured. By routinely collecting gas samples and comparing their composition to past measurements, scientists can track the geochemical evolution of the volcanic system and become aware of any subtle changes that might indicate a rekindling of eruptive activity. For more information, visit Volcanic Gas Monitoring at Mount Hood, Oregon.
USGS scientists and foreign students with the Center for the Study of Active Volcanoes' (CSAV) International Training Program recently visited Mount St. Helens to observe and learn about the volcanic deposits that record the eruptive history of the volcano. The students are part of a program to share volcano monitoring techniques and experiences, and build working relationships within the international community. Read The Columbian newspaper's story Scientists form volcanic bond at Mount St. Helens, watch a video and view a photo gallery of the field studies, online.
Volcano scientists from Ecuador, Colombia, Peru, Costa Rica, El Salvador, Canada, Indonesia, Italy, and Papua New Guinea, have been at CVO for the past couple weeks as part of a cooperative education program of the USGS and the University of Hawai`i, with support from the joint USGS-USAID Volcano Disaster Assistance Program. Through in-class instruction and field exercises at Mount St. Helens and Mt. Hood, scientists learned about a variety volcano monitoring methods, data analysis and interpretation, volcanic hazard assessment, and rapid response during volcanic crises. The knowledge will be used by the students to help prepare citizens for volcanic eruptions. Learn more at the Center for the Study of Actives Volcanoes.
USGS-CVO Research Geophysicist Jeff Wynn was awarded a 3rd patent for developing a new method of mapping and characterizing hydrocarbon plumes in seawater. As designed, an array of multiple streamer cables with electrical transmitters and receivers are towed in the sea behind a ship. As the streamer passes through a hydrocarbon plume, the receivers detect a capacitive response produced by the hydrocarbons. A data-acquisition system onboard the ship processes the signals to develop detailed maps of plume locations, and can be used to track and characterize how the plume changes over time. In sea-trials, the system also turned out to be well-suited to locating buried metallic infrastructure and old shipwrecks.
The IDES (Increasing Diversity in Earth Sciences) Program seeks to strengthen the understanding of Earth science and its relevance to society among broad and diverse segments of the population. Recently, CVO IDES student intern Joe Bard and geologist Dave Ramsey met with IDES students on a field trip to Newberry Volcano, to talk about the geology of the area, the recently-published geologic map database (USGS Data Series 771), and volcano hazards. Click on the link to find out more about IDES.
Modeling is becoming an increasingly important tool for interpreting observations and understanding the complexity of volcanic systems. A physics-based model, as described in Bayesian inversion of data from effusive volcanic eruptions using physics-based models: Application to Mount St. Helens 2004–2008, links data collected during the recent eruption to show that magma under Mount St. Helens likely resides between 8 and 16 km (5 to 10 miles) below the crater floor in an elongated chamber with a width of roughly 2 km (1.2 miles). Future work will help to create a more sophisticated model to improve on these estimates. To the extent that a model is a reasonable representation of a volcanic system, comparing model predictions with actual data can be used to infer properties of the volcanic system at Mount St. Helens and at other active volcanoes.
Recent field observations of Crater Glacier show the glacier terminus has advanced about 40 meters (about 131 feet) since June 2012. The glacier is moving at an average rate of about 11 cm per day (4.3 inches) -- roughly the distance from your wrist to the tip of your thumb (per day). The glacier continues to calve into the head of Loowit stream. Read more about Glaciation at Mount St. Helens, online.
The shield-shaped Newberry Volcano (central Oregon) is the product of deposits from thousands of eruptions, including at least 25 in the past 12,000 years. This geodatabase, used to produce U.S. Geological Survey Miscellaneous Investigations Series Map I-2455, provides information on Newberry rocks and deposits based on their composition, age, and lithology, along with locations of vents, hydrothermal features and even craters pocking the surface of the Big Obsidian Flow. Also included are links to view or print the map sheets and the accompanying pamphlet. View the Database for the Geologic Map of Newberry Volcano, Deschutes, Klamath, and Lake Counties, Oregon: USGS Data Series 771, online.
The new Mount St. Helens Science and Learning Center webpage features eruption images and videos, time-lapse photos of ecosystem changes, volcano facts, publications, and ways to explore the volcanic landscape this summer. Visit the Mount St. Helens Science and Learning Center to learn more.
At the USGS-CVO, scientists conduct research about volcano hazards so that policymakers and the public can prepare adequately for the next eruption in the Cascades. Here are opportunities to engage USGS scientists and learn more about hazards in your area and how to be prepared.
Two educator training workshops are offered this summer at Mount St. Helens and Mount Rainier. The workshops feature informative talks on Cascade volcanoes and volcanic processes, ideas for classroom activities, hikes into the field, and tips for organizing school field trips to visit the volcanoes.
Other upcoming events for educators include:
Mount St. Helens seized the world's attention in 1980 when the largest historical landslide on Earth and a powerful explosive eruption reshaped the volcano, created its distinctive crater, and dramatically modified the surrounding landscape. Read about what has happened at the volcano since 1980 in a new USGS Fact Sheet, "Mount St. Helens Then and Now--What's Going On?" The digital version contains six embedded videoclips to help learn about the dramatic changes taking place on and beneath this active volcano.
Meet scientists of the USGS Volcano Science Center and learn more about their jobs as they watch over 169 known active volcanoes within the US and its territories. These two-to-four-minute web shorts provide glimpses into some of many professions that contribute to the science of volcanology.
The Three Sisters are a cluster of volcanoes near Bend, Oregon, that bear little family resemblance. North Sister is the elder, now a glacially ravaged stratocone that consists of hundreds of thin rubbly lava flows. Middle Sister is an andesite-basalt-dacite cone, with gentle-sloping west flank and steep east face. Snow and ice fills the youngest cone, South Sister, a bimodal rhyolite-to-intermediate composition edifice that was constructed within the last 50,000 years. The authors of this new geologic map spent about one month each summer from 2000 to 2009 mapping the volcanic field on foot and collecting samples for geochemical analyses. View the product of their efforts, Geologic Map of Three Sisters Volcanic Cluster, Cascade Range, Oregon.
Earlier this month, members of the Volcano Disaster Assistance Program (VDAP) helped lead a workshop with Latin American Volcano seismologists in Manizales, Colombia. The workshop brought together seismologists and volcanologists from 12 nations in Latin American and the Caribbean to share information and improve seismic methods to forecast volcanic eruptions. USGS scientists discussed a global data set of observed patterns of precursory earthquakes, use of seismic data to monitor volcanic debris flows, and participated in discussion groups on infrasound and a variety of other topics related to eruption prediction. For more information on VDAP’s work, visit the Volcano Disaster Assistance Program website.
The Mount St. Helens website has been updated with a new design and the most recent scientific research about its rich volcanic history. The change was made as a part of the ongoing update to all Volcano Hazards Program webpages. We hope you enjoy this new learning experience about the most active volcano in the contiguous U.S. Photo from October 5, 2004.
A new video shows changes inside Mount St. Helen's crater from 2004 to 2012. The images were created from aerial photographs that were processed with photogrammetry software to collect a 3-D point cloud, which was then used to create shaded relief digital elevation models (DEMs). Information regarding volume and rates of growth of the lava dome and Crater Glacier are extracted from DEMs and used to monitor surface changes in the crater. View the time-series online, Time-series of dome and glacier growth at Mount St. Helens, Washington, 2004-2012. You can also view camera-captured time-lapse for this same period but from a different perspective. Images taken by a remote camera on the northwest flank of the volcano show dome growth and the movement of Crater Glacier across the crater floor. Watch Mount St. Helens' Runaway Glacier.
Field work continues at the volcano. The focus of winter work is primarily on maintaining remote monitoring equipment, making direct observations of the impacts of storm events, and measuring the transportation of sediments in swift moving streams. The work is necessary to keep the early warning systems functional, assess hazards, and engage in mitigation measures, if needed. View the Winter 2013 Fieldwork images online.
Crews visited the Spirit Lake gaging station at Mount St. Helens to correlate the water level on a staff outside the station with readings from pressure transducers inside the tunnel. The outlet of Spirit Lake was dammed by a debris avalanche during the May 18, 1980 eruption. In 1985, a tunnel was constructed so that as the level of the lake rises, water flows through the tunnel to South Coldwater Creek. Logs and other debris floating in the lake can become lodged near the tunnel opening. The transducers are used to track water level changes inside the tunnel. By comparing the water level changes in the tunnel with the lake level measured at the gaging station, scientists can determine if the logs are stacking up, and potentially, blocking the tunnel entrance. Read station notes and find data online at the Spirit Lake at Tunnel gaging station.
Over 90,000 maps and reports by more than 600 publishers are available in one location - on the recently redesigned National Geologic Map Database. Users can go online to view geologic, geophysical, natural resource and hazard maps for many locations within the United States. Popular formats make the database easy to use. What is the geology of your backyard? Find out by searching The National Geologic Map Database.
We are currently upgrading our website to provide a new look and improved functionality. When completed, the website will offer streamlined access to information about volcano hazards and preparedness, maps, images, monitoring data, and volcano histories. We apologize for any inconvenience while this process is underway.
CVO scientists John Ewert, Nate Wood, and Willie Scott conducted a FEMA Volcanic Crises Awareness Course at the local emergency management agency (Clark Regional Emergency Services Agency or CRESA). The course, developed by the National Disaster Preparedness Training Center at University of Hawaii with substantial contributions from other USGS scientists, provides an overview of volcanic processes and hazards, current monitoring and hazard assessment tools, volcano warning systems, and community preparedness. The course is designed to assist decision-makers, emergency managers, response personnel, planners, and other professionals from both public and private sectors in understanding and preparing for future volcanic crises. For more information on emergency preparedness and how you can be ready, visit CRESA.
The 1980 eruption of Mount St. Helens, Washington, clogged the upper reaches of the North Fork Toutle River with sediment. In 1989, the U.S. Army Corps of Engineers completed a Sediment Retention Structure (SRS) to minimize the downstream transport of the sand, silt and gravel. Since construction of the SRS the sediment trap has filled to more than 50 percent of capacity, but its efficiency has diminished and sediment is bypassing the structure. CVO Geophysicist Roger Denlinger conducted numerical simulations to assess the ability of the structure to withstand potential large flow events, either from debris flows or from sediment-laden floods. In the model, large debris flows originating from release of lake water or from an eruption of Mount St. Helens never topped SRS, but instead filled the braided channels upstream of the SRS. These types of flows would however, reduce sediment storage capacity in the future. Read Effects of catastrophic floods and debris flows on the sediment retention structure, North Fork Toutle River, Washington, online. You can also check out discharge data from the North Fork Toutle River station located below the SRS. In 2012 the U.S. Army Corps of Engineers raised the level of the spillway to trap additional sediment.
CVO Scientists John Ewert, Andy Lockhart, Peter Kelly, and Chris Lockett were featured in a short program about volcanic hazards and the evolution of the monitoring techniques aimed at understanding volcanic behavior. The catastrophic eruption of Mount St. Helens in 1980 re-emphasized the need to closely study and monitor Cascade volcanoes by analyzing the seismicity associated with magma or other fluids moving under the volcano, the swelling of a volcano’s flanks, and the type and amount of volcanic gases emitted. With so many people and infrastructure located near potentially active Cascade volcanoes, it is important to have integrated, continuous monitoring networks so people can be prepared for the next eruption. Watch the story Deceptive Beauty: Volcanoes Ready to Blow, online.
When magma rises towards the Earth's surface, it produces emissions of sulfur dioxide and other gases. Scientists use miniature spectrometers to measure the absorption of light as it passes through a volcanic plume to determine the concentration and emission rate of gases in the plume. CVO post-doctoral researcher Christoph Kern, with support from colleagues from CVO, the University of Heidelberg and the Hawaiian Volcano Observatory, has developed a new method for evaluating spectroscopic data that takes into account the different paths light can take on its way through the plume. Using the new technique, the researchers are now able to make significantly more accurate assessments of degassing activity at Kilauea volcano (Hawaii) and at other active volcanoes. Monitoring the changes in emission rates of sulfur dioxide is very important for understanding volcano behavior and determining volcanic hazards.
Read Improving the accuracy of SO2 column densities and emission rates obtained from upward-looking UV-spectroscopic measurements of volcanic plumes by taking realistic radiative transfer into account, online.
USGS-CVO research geophysicist Jeff Wynn is an author on an article in Sea Technology magazine describing a USGS-developed technology to map the sub-seafloor for placer heavy minerals, buried wrecks, and trenched cables. Using the marine induced polarization technique, a ship tows an instrument array through the water or along the sea floor. An electrical signal is sent through the array and the secondary response is measured. The frequency of the response is diagnostic of certain deposits beneath the seafloor and could also be used to monitor biodegradation of an oil plume in real time in the deep ocean. Laboratory measurements indicate that the induced polarization technique can detect and map oil in the seawater column down to below 0.1% by volume. Read an excerpt from Induced Polarization for Subseafloor, Deep-Ocean Mapping, online.
Geologist Dave Ramsey and research collaborator Lee Siebert led groups of high school students from Kelso and Longview, Washington-area schools on interactive hikes of the Hummocks Trail at the Mount St. Helens National Volcanic Monument. The hikes were part of a STEM (Science, Technology, Engineering, and Math) initiative coordinated by the Southwest Washington Workforce Development Council and designed to give students experience with scientific investigations in the field and laboratory. On the hikes, students learned about the techniques used by scientists to understand the formation of the hummocks that occurred as a result of the massive debris avalanche of the May 18, 1980 eruption. For more information on exploring Mount St. Helens, visit the Mount St. Helens National Volcanic Monument webpage.
Glacier Peak is the most remote of the five active volcanoes in Washington State. It is not prominently visible from any major population center so its hazards tend to be over-looked. Since the end of the last ice age, Glacier Peak has produced some of the largest and most explosive eruptions in the state. CVO Geologist Jim Vallance is studying Glacier Peak’s tephra deposits to determine precisely when and how often the volcano has erupted, and the size of past eruptions. For more information, see the USGS Fact Sheet, Glacier Peak - history and hazards of a cascade volcano.
Diamond Craters is one of several young basalt lava fields dotting southeastern Oregon. Active between about 7320 and 7790 years ago (calibrated ages), the entire eruptive episode was less than 100 years in duration. Read more about Diamond Craters and the techniques scientists use to find the age of young lava flows and figure out how long eruptions last, in a new paper titled: Age and duration of volcanic activity at Diamond Craters, southeastern Oregon.
Scientists from CVO (VDAP) are working together with Indonesian scientists to support and enhance the Government of Indonesias' Center for Volcanology and Geologic Hazard Mitigation’s volcano monitoring and response capabilities. Five Indonesian scientists visited CVO in September, exchanging ideas and techniques for volcano monitoring and hazard assessment. The group observed hazards at Cascades volcanoes and traveled to Alaska to learn about how volcanic ash-aviation issues are handled in the US from colleagues at the Alaska Volcano Observatory, the Federal Aviation Administration and the National Weather Service. Indonesia is a country where more than 3.3 million people live very closely to active volcanoes. Through improved monitoring and warning systems, citizens can be warned of volcanic events to avoid harm. For more information on the U.S.-Indonesia efforts, read U.S. and Indonesia Partner to Reduce the Risk of Volcano Disasters and Save Lives. To learn about VDAP, see more at Volcano Disaster Assistance Program.
USGS Geologist Richard Waitt examines the deposits of pluvial Lake Chewaucan (Pleistocene), near Summer Lake, Oregon. The light colored horizontal lines are layers of ash from southern Cascade eruptions that fell on the lake, settled to the bottom and were covered by mud. This sequence represents a time period of roughly 50,000 years. Find out about ashfall hazards at Volcanic Ash: What it can do and how to prevent damage.
Recent articles in The Seattle Times discuss the completed maintenance of volcano monitoring sites at Mount Rainier and link to new photos of one of the highest remote stations in the Cascade Range. Read the stories online, Quake monitors on Mount Rainier ready and waiting, and Not just any day job: the view from 11,000 feet.
During the first week of September, scientists completed scheduled maintenance at five volcano monitoring stations between 7,000 and 11,000 feet on Mount Rainier. Work was completed by staff from the USGS Cascades Volcano Observatory (CVO) and Pacific Northwest Seismic Network (PNSN), with strong support from Mount Rainier National Park (MRNP). The stations provide continuous data streams that are critical for detecting signs of unrest at Mount Rainier. View Mount Rainier Monitoring information and a Photo Gallery of this work.
Researchers at CVO perform flume experiments to test mathematical models for interpreting and forecasting debris flow behavior. Up to 40 tons of sediment are placed behind a gate at the head of a 310-feet long flume, saturated with water and released. Data collection ports in the floor of the flume measure the forces due to particles sliding and colliding at the base of the flow, while photos and videos record surface effects. The experiments lead to development of technologies for mitigating debris flow hazards, including automated detection and warning systems and engineering countermeasures, to protect high-risk areas such as Mount St. Helens, Redoubt Volcano in Alaska, and Pinatubo Volcano in the Philippines. See past experiments at Video Documentation of Experiments at the USGS Debris-Flow Flume 1992–2006 (amended to include 2007–2009).
U.S. Geological Survey Cascades Volcano Observatory (CVO) personnel will be working in Mount Rainier National Park (MRNP) from September 4-7 to perform repairs, upgrades, and maintenance at 5 monitoring stations on the volcano. Installed in 2007-2008, the stations provide a continuous stream of real-time seismic and deformation measurements from one of the most hazardous volcanoes in the Cascade Range. A helicopter under contract to the National Park Service will assist with the high-elevation work (7,000 – 11,100 feet).
The fieldwork will be carried out by a team of 10-12 people from CVO, who will also support a University of Washington team performing similar maintenance on a remote seismic station operated by the Pacific Northwest Seismic Network (PNSN). The CVO stations, in conjunction with those from the PNSN seismic network, provide continuous data streams that are critical for detecting signs of unrest at Mount Rainier. In addition, data from the combined network is creating research opportunities for USGS and academic scientists who are investigating the inner workings of the volcano as well as studying several recent seismic swarms.
Recent articles in The Columbian describe the Mount St. Helens monitoring site upgrades and early preparations for the study of the magmatic system underneath the volcano. Read the stories online, Upgraded equipment aims to take St. Helens' pulse, and 2014 study of St. Helens magma system will be among world's largest.
CVO geologist Dave Ramsey stands on top of Wizard Island in the Crater Lake caldera, holding his Crater Lake Revealed poster. The poster, prepared from this same perspective, shows the geology of the lake floor from its deepest basins to shoreline. Mr. Ramsey was at Crater Lake to take part in an educational field trip on the geologic history and hazards of the area. Download the poster Crater Lake Revealed for your next trip to Crater Lake National Park.
Mount St. Helens is an active volcano, continuously monitored for earthquakes, ground deformation, erosion and debris flows. Clear, summer weather provides an opportunity to access remote monitoring sites for necessary repairs, to observe, quantify and track changes from previous years, and conduct new research. The image gallery, Mount St. Helens 2012 Fieldwork, highlights the summer work completed on the flanks of the volcano as well as in the crater.
On the northern flank of Mount St. Helens (Dogs Head lava dome in the background), Mike Clynne maps the surficial extent of a debris flow. Mount St. Helens has a rich and complex 300,000-year history of explosive eruptions, lava flows, dome building and debris flows. Mapping these deposits gives insight into the volcano’s eruptive past and provides a practical understanding of the geology of this area. To learn more about Mount St. Helen’s eruptive past, read Pre-1980 Eruptive History of Mount St. Helens, Washington.
While conducting routine field work at Mount St. Helens, 13-14 mountain goats were spotted one-half mile upstream of Loowit Falls. The goats crossed the Loowit canyon and headed east, climbing rough volcanic terrain to disappear around the eastern flank of the mountain. Goats have become year-round residents at the volcano, likely traveling from nearby Mount Adams or Goat Rocks to find new habitat. Read about mountain goat ecology and where to view goats at the Washington Department of Fish and Wildlife conservation webpage.
On the weekend of July 28, hikers in Canyon Creek Meadows near Three Fingered Jack (central Oregon Cascades) were surprised to find boulders and mud coating the west end of the meadow. The deposits are from a recent debris flow caused by a partial breach of a lake dammed by a young glacial moraine at the snout of tiny “Jack Glacier.” The sudden outflow from the lake incorporated rocks, sand, and mud that was deposited in a bouldery fan at the foot of the moraine with muddy water flooding the meadow and flowing into Canyon Creek. The trigger for the breach is not yet known. Such events, including two in Canyon Creek Meadows during the latter half of the 20th century, have been documented at numerous moraine-dammed lakes in the Mount Jefferson and Three Sisters area. To learn more, read Debris flows from failures of Neoglacial-age moraine dams in the Three Sisters and Mount Jefferson wilderness areas, Oregon.
Christoph Kern sets up a UV spectrometer to detect volcanic gases rising from fumaroles at Crater Rock on Mount Hood. The instrument measures the spectrum of light passing through volcanic gas and identifies individual gas species by their unique absorption “fingerprints”. The equipment is sensitive enough to detect mixing ratios of less than a part per million (one molecule of volcanic gas per one million molecules of air). In this case, the spectrometer detected low amounts of sulfur dioxide gas, similar to those found in measurements taken here last year. For more information, visit the Volcano Emission Project.
Marc Biundo and Bryan Holmes climb to Camp Schurman, at the base of Steamboat Prow on Mount Rainier (elevation 9500 feet), to check GPS equipment, troubleshoot radio telemetry, and conduct radio tests to new receiver sites off of the volcano. A Global Positioning System (GPS) was installed at the climbing hut in 2007 to monitor subtle movements of the volcano. The data shows the mountain moves several millimeters per year to the north and east, following a regional tectonic trend. Because of its location near to large population centers and the nature of the potential hazards, the USGS installed monitoring networks to be able to detect the onset of volcanic activity at Mount Rainier at the earliest possible moment. To learn more, visit the Pacific Northwest GPS Monitoring Network.
Workshop participants Tiffany Fuller and Lucas Jones reach Pinnacle Saddle, south of Mount Rainier, during an afternoon session of experiential learning. Each year, personnel from CVO and the National Park Service provide a week-long course for teachers to learn about volcanic processes, hazards, and human-volcano interactions while exploring Mount Rainier National Park. The workshop materials, which include more than 30 student activities and a field guide to geological sites of interest within the Park, is designed for middle school teachers interested in teaching about this and other Cascade peaks. To browse the activities and learn more, visit Living with a Volcano in Your Backyard: An Educator’s Guide to Mount Rainier.
A scientist (lower center) walks along the leading edge of rock debris carried downslope by Crater Glacier, documenting evidence of glacial advance into the Loowit stream channel. The glacier continues to advance at approximately 10 cm per day (about the length of a computer mouse) although the rate of advance has slowed since the 2004-2008 lava dome building ended. To learn more about Crater Glacier and see an animation of the glacier’s movement, visit Photographic Documentation of the Evolution of Crater Glacier, Mount St. Helens, Washington, September 2006–November 2009.
As snow melts from the upper reaches of Mount St. Helens, CVO scientists access remote monitoring sites to repair and replace equipment damaged by harsh winter weather. Here, the team refurbishes an acoustic flow monitor (AFM) located above the Loowit River. The AFM was designed by the USGS-CVO to detect and monitor debris flows through ground vibrations and transmit the data in real-time. AFMs are a key component of early warning systems in valleys threatened by such flows. To learn more, read about Hydrologic Monitoring of Volcanoes.
Newberry Volcano is the first of the CVO volcanoes to showcase the updated website design. The new web pages include more information about the large central Oregon volcano than the old CVO website offered. We hope you enjoy the new look and enhanced information!
Outside of Portland, Oregon, the Marmot Dam blocked the Sandy River for more than 90 years. A combination of economic and environmental issues resulted in the removal of the dam in 2007, allowing the river to flow freely over its entire length. In the hours, days and months following the breach, the USGS monitored the erosion, transport, and deposition of sediment downstream. The energetic Sandy River responded rapidly, removing a large amount of reservoir sediment in the first year. The erosion rate and channel widening diminished with time. A newly published USGS report, in collaboration with scientists at Federal agencies, academic institutions, and private companies, describes the two-year transition along the Sandy River.
How did an eruption in Alaska, 1200 miles from Seattle, affect life in the Pacific Northwest 100 years ago this week? Learn how the June 6, 1912 eruption of Novarupta, near Katmai, Alaska affected life in the Pacific Northwest, and how future volcanic ash fall can disrupt our lives.
May 18, 2012 marks the 32nd anniversary of Mount St. Helens' catastrophic eruption, the first volcanic eruption in the conterminous United States since the 1915 eruption of California's Lassen Peak. View archive photos of Mount St. Helens. Read a summary of events. Learn about the 1980 eruptions. Download a 2012 panorama of Mount St. Helens, and modern photos of the volcano and ongoing monitoring.
View article in The Columbian newspaper about work of the USGS Cascades Volcano Observatory.
Following two weeks of fieldwork, a three person team from the USAID-USGS Volcano Disaster Assistance Program (VDAP) has returned from Colombia where, at the request of the Servicio GeolÃ³gico Colombiano (SGC; Geological Survey of Colombia), they were working to support the monitoring and eruption forecasting efforts at Nevado del Ruiz volcano. Photo shows USGS and SGC personnel working at a lahar (volcanic debris flow) detection and warning instrument site high on the flanks of Ruiz. An eruption from Nevado del Ruiz on November 13, 1985 caused over 23,000 deaths as several towns were overrun by rapidly moving volcanic debris flows. Recently, Ruiz has been showing signs that it may erupt again. To learn more about VDAP, which is based at the USGS Cascades Volcano Observatory, please visit the VDAP website.
USGS will conduct a variety of volcano-related trainings for emergency managers, aviators, health care personnel, park interpreters, and school students. See volcano preparedness materials highlighted on the 'In-Focus' web page of Washington Military Department’s Emergency Management Division. Find volcano information and educational opportunities at this website. Read the news release.
Three USGS volcanologists from the Cascades Volcano Observatory are working with our counterpart organization, the Center for Volcanology and Geological Hazards Mitigation, to install real-time GPS monitoring on Agung Volcano and to evaluate recent seismicity. Recent satellite measurements show that the volcano has been slowly inflating over the past several years. Agung is an active and dangerous volcano located on Bali, which in 1963 produced an eruption that killed more than 1000 people. The 1963 Agung eruption was similar in magnitude to the 1980 eruption of Mount St. Helens. Monitoring infrastructure enhancement is part of our Volcano Disaster Assistance Program, a partnership of the USGS and the U.S. Agency for International Development. In the photo a solar-powered GPS installation on Agung’s flanks is nearing completion. Data from this and other installations will be used to continuously measure movements of the volcano flanks and will be used with seismic and other data to provide forecasts of eruptive activity.
On April 20, a three person team from the USAID-USGS Volcano Disaster Assistance Program (VDAP) is traveling to Colombia at the request of the Instituto Colombiano de Geologia y Mineria (INGEOMINAS), to support volcano monitoring and data analysis activities at Nevado del Ruiz volcano, which has been showing signs that it may erupt soon. An eruption from Nevado del Ruiz on November 13, 1985 caused over 23,000 deaths as several towns were overrun by rapidly moving volcanic debris flows. To learn more about VDAP, which is based at the USGS Cascades Volcano Observatory, please visit the VDAP website.
Wading into the North Fork Toutle River (near Mount St. Helens, Washington), USGS Hydrotech Tami Christianson collects a water and sediment sample from mid-stream. Erosion of the huge debris avalanche deposit emplaced on May 18, 1980, continues to generate high sediment loads. Some is trapped behind the U.S. Army Corps of Engineers Sediment Retention Structure (SRS), but increasing amounts are bypassing the structure and endangering fish habitat and increasing flood risks to downstream communities. Sampling above and below the SRS is done periodically to evaluate the performance of the structure.
CVO scientists Richard Waitt and David Ramsey are authors on a newly published geospatial (GIS) database of recent volcanic deposits on Augustine Volcano, Alaska. The publication, McIntire, J., Ramsey, D.W., Thoms, E., Waitt, R.B., and Beget, J.E., 2012, Database for volcanic processes and geology of Augustine Volcano, Alaska: U.S. Geological Survey Data Series 677 (database for USGS Professional Paper 1762, by Waitt and Beget), is available from the USGS publications website. Augustine is a frequently active island volcano in Cook Inlet.
Educators, read this announcement about Conversations with Scientists webinars. Programs are intended for middle and high school classrooms. The registration deadline has been extended through March 27th for the March 29th Crater Lake program.
Starting at approximately 22:00 pm PST on 7 March 2012, a small swarm of earthquakes has been occurring near Mount Hood. The earthquakes locate approximately 4 miles south-southwest of the summit of the volcano (~1 mile east of Government Camp) at depths of 2-4 miles. Between 22:00 PST March 7 and 16:00 PST March 9, over a dozen small earthquakes have been located by the Pacific Northwest Seismic Network (PNSN), with magnitudes ranging from 0.0 to 1.7. Typically, several earthquake swarms occur each year at Mount Hood, with some lasting for hours, others lasting for days to weeks. The March 7-9 swarm locates in roughly the same area as previous swarms, including swarms that occurred in February 1998 and September 2001. It is located 2-3 miles west of a swarm that occurred 22-23 February 2012.
For more details about Hood seismicity, visit the PNSN Mount Hood web page. For background information about swarms at Mount Hood, visit the PNSN web site for an excellent blog posting at PNSN Hood swarm blog
During August 2011, scientists and volunteers from the USGS Cascades Volcano Observatory (CVO) installed eight new real-time seismic and deformation (GPS) volcano monitoring stations around Newberry Volcano.
Over the last several months scientists at USGS-CVO and PNSN have been studying data from these new stations. They now have an adequate baseline understanding of activity at Newberry Volcano against which to compare future signs of unrest.
An Information Statement about the monitoring network was issued today.
The USGS and the US Forest Service have published a fact sheet about Newberry Volcano in Central Oregon. Learn about the geologic history, diverse styles of volcanism, volcanic hazards, monitoring and research at the largest volcano in the Cascades by reading the fact sheet on-line.
The U.S. ranks as one of the top countries in the world in the number of young, active volcanoes. The spectrum of volcanism includes explosive stratovolcanoes, effusive shield volcanoes, and restless calderas. Between 1980 and 2008, 43 volcanoes within the U.S. produced 95 eruptions and 32 episodes of unrest, the majority of which occurred in Alaska. A description and chronology of these eruptions and periods of unrest and a list of published literature is available at the USGS Publications Warehouse.
As the understanding of volcanic activity and hazards has grown over the years, so have the extent and types of monitoring networks and techniques available to detect early signs of anomalous volcanic behavior. This increased capability is providing us with a more accurate gauge of volcanic activity in the U.S. and at volcanoes monitored by CVO.
Mount St. Helens climbing permits are available for the 2012 summer season. U.S. Forest Service climbing permits are administered through the Mount St. Helens Institute which also offers a variety of educational programs related to Mount St. Helens. For more information, visit the U.S. Forest Service or Mount St. Helens Institute websites.
Beginning at approximately 12:30 pm PST on 23 February 2012 a small swarm of earthquakes occurred at Mount Hood. The earthquakes are approximately 4 miles south southeast of the summit of the volcano, and are occurring at depths of 3-5 miles. Between 12:30 PST Thursday and 8:00 PST Friday, more than 25 small earthquakes were located by the Pacific Northwest Seismic Network (PNSN), with magnitudes ranging from 0.1 to 1.7. Over the last 24 hours (through Saturday late-morning) no additional earthquakes occurred. Typically, several earthquake swarms occur each year at Mount Hood, with some lasting for hours, others lasting for days to weeks. The February 23-24 swarm locates in roughly the same area as previous swarms.
For more details about this swarm, visit the PNSN web site for an excellent blog posting about the swarm at PNSN blog as well as their Mount Hood seismicity map with locations of the swarm events at PNSN Mount Hood page
Beginning at approximately 12:30 pm PST on 23 February 2012 a small swarm of earthquakes occurred at Mount Hood. The earthquakes are approximately 4 miles south southeast of the summit of the volcano, and are occurring at depths of 3-5 miles. Between 12:30 and 2:30 there had been 15 small earthquakes ranging in magnitude from -0.2 to 1.8. Typically, several earthquake swarms occur each year at Mount Hood and this swarm is located in the same area as other previous swarms.
To see a map of where the earthquakes are occurring please visit the Pacific Northwest Seismic Network (PNSN) web site: PNSN
We are currently upgrading our website to provide a new look and improved functionality. When completed, the website will offer streamlined access to information about volcano hazards and preparedness, maps, images, monitoring data, and volcano histories.
Many of the links on this new home page will take you into the original CVO website, and these will gradually change as content is updated. Check back frequently.