Yellowstone Caldera Chronicles is a weekly column written by scientists and collaborators of the Yellowstone Volcano Observatory. This week's contribution is from Shaul Hurwitz, research hydrologist with the U.S. Geological Survey.
Have you ever wondered how Yellowstone Caldera was discovered, and how it was recognized as being the result of a massive volcanic eruption? In fact, the Yellowstone Plateau hosts three separate calderas, the youngest being the "Yellowstone Caldera". Our knowledge on how and when these three calderas formed is a result of many years of extensive field work and geologic mapping led by U.S. Geological Survey (USGS) scientist Bob Christiansen.
A caldera is large basin-shaped volcanic depression commonly formed when magma is withdrawn or erupted from a shallow underground reservoir. The removal of large volumes of magma results in loss of structural support for the overlying rock, thereby leading to collapse of the ground.
In the 1950s Joe Boyd, a doctoral student at Harvard University, carried out research on the rhyolite rocks in Yellowstone. Boyd recognized that some of the rhyolites were not lava flows, but rather tuffs (solidified deposits of ash that formed from explosive eruptions). He also identified a depression in the Yellowstone Plateau and suggested that it was related to the explosive eruptions. Boyd published his novel finding in a journal paper entitled "Welded tuffs and flows in the Rhyolite Plateau of Yellowstone Park, Wyoming". The causal link between the tuffs and the depression, however, remained unexplained.
Bob Christiansen was part of a USGS group that was tasked in 1965 with creating a comprehensive geologic map of the Yellowstone Plateau. Christiansen and his colleagues were asked to map the volcanic rocks that erupted during the Quaternary Period of Yellowstone, now recognized as the last 2.6 million years. The study was funded by several federal agencies including NASA, the National Park Service and the USGS. At the time, NASA was developing remote sensing instruments for satellites and needed test areas with good geologic maps to compare with the images captured from space.
Christiansen and his colleagues tried to understand when and how the volcano erupted, how much magma was vented, and where it went. Every year between 1966 and 1971 they spent three summer months in Yellowstone carrying out field work, often in very remote areas. In other times of the year, they analyzed aerial photographs, used microscopes to scrutinize slices of sampled rocks thinned to less than the width of a human hair (called "thin sections"), and measured the chemical composition of the rocks and their relative ages.
By 1972 the bulk of the geologic mapping was complete, and Christiansen and his colleague Dick Blank published the first report describing the volcanic history of the Yellowstone Plateau. Their findings revealed many of the details of Yellowstone's explosive volcanic past. They found that three large explosive eruptions were associated with formation of calderas. Based on potassium-argon dating by their USGS colleague John Obradovich, it was determined that the three large explosive eruptions occurred at 2.0, 1.2 and 0.6 million years ago. More recent results using more accurate dating methods revealed that these caldera forming eruptions took place 2.08 1.30, 0.63 million years ago.
Christiansen continued his work in Yellowstone for the next 25 years, mainly focusing his research on specific questions related to the volcanic history. His goal was to improve our understanding of the possible conditions that led to large eruptions. The comprehensive description of Yellowstone's volcanic history and the geologic map were published in 2001.
During that same year, Bob Christiansen became the founding Scientist-in-Charge of the Yellowstone Volcano Observatory. After 40 distinguished years with the USGS, he retired in 2004. Bob has described his time at Yellowstone in this interview. Today, Bob still continues his research as a scientist emeritus with the USGS in Menlo Park, California.
Yellowstone Caldera Chronicles is a weekly column written by scientists and collaborators of the Yellowstone Volcano Observatory. This week's contribution is from Michael Poland, geophysicist with the U.S. Geological Survey and Scientist-in-Charge of the Yellowstone Volcano Observatory.
To most people, the idea of a volcano "observatory" conjures image of a building that looks out at an active volcano, staffed by scientists who keep watch using an array of instrumentation. In many places, this is true. For example, the Hawaiian Volcano Observatory—one of the 5 observatories located in the United States—features a tower with a commanding view of the summit of KILAUEA, the most active volcano on Earth. In some parts of the world, having an observatory building with a good view of a volcano is critical for making measurements and collecting observations. The Yellowstone Volcano Observatory (YVO) is different, however—there is no building, and its diverse team of scientists is spread across the western United States.
One might expect that YVO is a scientist-staffed physical facility located within or near Yellowstone National Park. After all, Yellowstone is the largest volcanic system in the world, and bears watching! In fact, there is no actual structure to house YVO. What's more, YVO is not simply an operation of the U.S. Geological Survey (USGS). Instead, it is a consortium of partners who share the goal of monitoring and better understanding Yellowstone's volcanic activity. These characteristics make YVO unique among the volcano observatories of the world.
Let's start with the lack of a building. That may seem odd, but there is no need for an on-site presence. Yellowstone is far too vast for a single point to provide a suitable observation post. The only place with a commanding view of the area is on top of Mount Washburn (elevation 10,243 feet), and that spot is not accessible most months of the year due to Yellowstone's harsh winters.
The volcanic system has also not experienced an eruption of magma for about 70,000 years, when the most recent lava flow was emplaced. Visual observations of volcanic activity are therefore not critical for monitoring Yellowstone's activity. Regardless, the National Park Service staff, as well as some private citizens, provide abundant on-site observations of thermal and geyser activity, so there is certainly a "boots on the ground" presence at Yellowstone.
Finally, Yellowstone is host to a vast array of instrumentation that is constantly recording data that can be accessed via the Internet. This includes not only the seismic and deformation stations, but also records of water levels and chemistry, temperatures of thermal areas, and other geological information. These data can be viewed by scientists across the country in real time with just a few clicks of a mouse, and without the need to travel to Yellowstone. Indeed, the YVO Scientist-in-Charge has never resided in the Yellowstone area. The park geologist, however, does live on site and represents YVO when needed.
This brings us to the second unique aspect of YVO—that it is not an operation run by USGS, but rather a consortium of agencies: USGS, the National Park Service, the University of Utah (which operates the Yellowstone seismic network), UNAVCO (which maintains GPS stations, borehole tiltmeters and strainmeters, and lake monitors within Yellowstone National Park), the University of Wyoming, the Montana Bureau of Mines and Geology, the Wyoming State Geological Survey, and the Idaho Geological Survey.
The consortium includes scientists with extensive experience in volcanology. The research and monitoring work accomplished by these scientists is critical to not only understanding what is happening beneath the ground, but also to determining whether or not any hazardous activity may be imminent. In the event of a crisis, all of the partners would come together in Yellowstone National Park to assess potential outcomes and provide expert guidance to emergency managers.
Although this non-traditional approach to a volcano observatory would not work everywhere, it has served YVO well since its founding in 2001. So the next time you think about YVO, don't think of a building. Rather, think about the large team spread across the western United States that is collaborating behind the scenes to provide the best and most current information about Yellowstone volcanism.
Welcome to the inaugural issue of "Yellowstone Caldera Chronicles," a new weekly column of the Yellowstone Volcano Observatory (YVO). Each Monday on the YVO homepage, we'll post a new article that covers a different topic, including geology, history, current activity, and other subjects. The articles will be written by YVO scientists and others who study Yellowstone's volcanic system.
The publication of the first issue of Yellowstone Caldera Chronicles on New Year's Day of 2018 provides an excellent opportunity to review the activity that occurred in Yellowstone over the past year. And what a year it was!
2017 began calmly enough. In the first several months of the year, only a few hundred earthquakes were located by the University of Utah Seismograph Stations, which has the lead in monitoring seismic activity in the Yellowstone region. This trend continued the low earthquake rates of 2015 and 2016, during which only about 1,000 earthquakes were located per year (typically, between 1,000 and 3,000 earthquakes are located in any given year).
All of this changed on June 12, when the Maple Creek earthquake swarm began on the west side of the Park, a few miles north of West Yellowstone, Montana. Over the ensuing three months, about 2,400 earthquakes were located by the University of Utah Seismograph Stations (many more earthquakes occurred but were too small to be located). The swarm lasted until early September, and small bursts of seismicity occurred in the same area in late September and late October. The largest event in the sequence was an M4.4 event on June 16.
Additional swarms of earthquakes occurred outside the Yellowstone area, near Lincoln, Montana, and Soda Springs, Idaho. These swarms were each kicked off by widely felt M5+ earthquakes, but the seismicity is not related to the Yellowstone magmatic system. Instead, the earthquakes are caused by faulting associated with tectonic extension of the western United States.
Overall for the year, over 3,300 earthquakes, including about 20 that were felt, were located in the Yellowstone region, making 2017 one of the most seismically active years ever recorded. Almost 80% of all the earthquakes that were located occurred as part of approximately 13 swarms, of which the Maple Creek swarm was by far the largest. But was that swarm the largest ever recorded at Yellowstone?
In fact, the 2017 Maple Creek swarm comes in a distant second to that of 1985. In that year, an earthquake swarm also near West Yellowstone, Montana, lasted for 3 months and included over 3,000 located earthquakes, with the largest reaching M4.9. If today's monitoring system had been in place in 1985, it is likely that many more earthquakes would have been located. The 2010 Madison swarm, just southwest of West Yellowstone, is now the third largest swarm ever recorded, with about 2,300 located events.
Interestingly, the 1985 and 2010 swarms were associated with a change in deformation style of the caldera. During both years, the caldera switched from uplift to subsidence, suggesting that the swarms were associated with a release of fluids from the caldera region.
In 2017, however, there was no significant change in deformation at the time of the swarm. Throughout most of the year, the caldera subsided and the area around Norris Geyser Basin continued to uplift, as indicated by numerous continuous Global Positioning System stations in the region. Both caldera subsidence and Norris uplift have been ongoing since 2015. In early-December, however, that pattern began to change, with subsidence beginning at Norris. Whether this pattern will continue remains to be seen.
Instead of being related to fluid migration, it is also possible that the Maple Creek earthquake swarm is a lingering effect of the 1959 M7.3 Hebgen Lake earthquake—the largest earthquake ever recorded in the Yellowstone region. Future research will help to unravel this story.
We will be sure to update you on the results of our research in this column, so stay tuned for more information in the months to come. In the meantime, we hope you enjoy this recurring column, and we look forward to sharing interesting stories and new information every week.
The many members of the YVO consortium wish you and your loved ones a wonderful start to 2018. Happy New Year!
YVO scientists were busy in October 2017. During that month, a number of field measurements were completed in Yellowstone National Park, and some instruments that had been recording data throughout the summer were recovered before the onset of the harsh Rocky Mountain winter. This included 12 semipermanent Global Positioning System (GPS) stations that had been in place since the spring—part of an annual campaign, now 10 years and still running, aimed at improving our understanding of how the ground deforms due to magmatic and hydrothermal activity in the Yellowstone region.
Together with frequent earthquakes, vigorous hydrothermal activity, and abundant emissions of volcanic gases, relatively slow movements of the ground surface attest to ongoing activity in the vast magmatic-tectonic system beneath Yellowstone National Park. Imperceptible to the naked eye, episodes of uplift, subsidence, and stretching or contraction of the surface are monitored by repeated surveys and networks of sensitive instruments operated by YVO and its partners. The process is called deformation because it changes the shape of the land surface in subtle but detectable ways. Since the first leveling survey along Park roads in 1923, the central part of the caldera floor has moved up nearly 1 meter (about 3 feet). But the uplift hasn't been steady. Annual leveling surveys from 1983 to 2007 revealed periods of subsidence lasting up to a decade. More recently, scientists using a satellite radar technique called InSAR have discovered that both the pattern and rate of surface deformation change over time. Such movements are part of normal background activity at one of Earth's largest active magmatic systems.
One of the tools that scientists use to keep track of surface deformation is the same GPS technology that you might use to navigate while driving your car. With specialized equipment and data processing techniques, the location of a GPS monitoring station can be measured very precisely, to within about 1 millimeter (less than the thickness of a dime). YVO and its partners, the University NAVSTAR Consortium (UNAVCO) and University of Utah, have installed a network of more than two dozen such stations in and around Yellowstone National Park to track surface deformation. The stations operate continuously, and data are processed at several locations to obtain daily positions. Small movements of the stations with respect to one another reveal the pattern of surface deformation over time.
The continuous GPS network cannot cover all areas in Yellowstone National Park, so YVO scientists have devised a less invasive GPS technique called semipermanent GPS (SPGPS). As the name implies, SPGPS stations are temporary. A network of SPGPS stations is installed each year from spring through autumn, avoiding months with heavy snowfall that can bury GPS antennas. This arrangement allows SPGPS stations to be smaller than continuous GPS installations—a distinct advantage in ecologically sensitive areas like Yellowstone. The trade-off, of course, is that SPGPS stations only acquire data when they are deployed. Despite the winter data gaps, SPGPS data have been useful for tracking movements of the caldera floor and an active area along the north caldera rim centered near Norris Geyser Basin. For example, on March 30, 2014, a magnitude 4.8 earthquake—the largest Yellowstone quake in 34 years—shook the Norris area. Nearby SPGPS stations that had been deployed only a few days earlier recorded a sudden reversal from uplift to subsidence that coincided with the timing of the quake. Combined with data from the continuous GPS network and InSAR observations, the SPGPS results helped to identify the location and depth of the deformation source. SPGPS may also prove useful for investigating the summer 2017 earthquake swarm north of West Yellowstone, MT. A SPGPS station at Horse Butte is only 15 km west of the swarm's center. Analyzing the data from the station, which was recovered in late October, might prove useful to understanding the cause of the earthquakes and any associated ground motion. Stay tuned—we'll post details about the 2017 SPGPS results to the YVO website over the winter!
On September 1, I succeeded Jake Lowenstern as the Yellowstone Volcano Observatory (YVO) Scientist-in-Charge. To say I have some big shoes to fill is an understatement. During his 15 years in the position, Jake oversaw the growth of YVO into a collaborative consortium of eight organizations, helped guide the expansion of geophysical and geochemical monitoring, encouraged (and also initiated!) a broad array of research, and tirelessly advocated for communicating and sharing the wonders of Yellowstone with the world. I can never replace Jake, but I hope to prove an effective steward of his efforts, and I will continue to advance the goal of improving our knowledge of the inner workings of Yellowstone as well as other volcanic systems in the United States and, indeed, around the world.
My first visit to Yellowstone National Park was 30 years ago, when my family gathered for a reunion camp out at Grant Village on the shores of West Thumb. The memories of that experience are vivid, from waiting patiently for Old Faithful to erupt, to contributing to a "bison jam" in Hayden Valley. In subsequent years, I visited the Park on numerous occasions, both on vacation and professionally as I pursued a career in Earth science. The Park captivated my imagination and helped to stimulate my interest in geology, and I am pleased to now be able to play a small role in helping to grow our understanding of Yellowstone's behavior.
My USGS career began in 2002 at the Cascades Volcano Observatory, where I was tasked with developing a capability for assessing ground deformation using radar data from orbiting satellites. A high point of my time in the Cascades was in 2004, when I was part of the team that responded to the reawakening of Mount St. Helens—my first experience in responding to a volcanic crisis. I also was able to make numerous trips to Yellowstone as part of USGS efforts to map ground deformation throughout the caldera system. This work had me collaborating closely with Dan Dzurisin, whose studies have redefined how we view the behavior of volcanic calderas.
In 2005, I moved to the Island of Hawaii, where I spent 10 years conducting research as a staff member at the Hawaiian Volcano Observatory. I was very lucky to not only work with many talented scientists, but also to experience some incredibly dynamic volcanic events and earthquakes—the M6.7 Kiholo Bay earthquake in 2006, the start of Kilauea's currently ongoing summit eruption in 2008, and a "curtain of fire" fissure eruption at Kilauea in 2011, to name a few. My scientific explorations, done in collaboration with numerous Observatory and university scientists, focused on figuring out the patterns of ground deformation over time (especially using satellites), understanding the changing rates of magma supply to the volcanoes of Hawaii, and using microgravity measurements to map changes in subsurface magma storage.
I returned to the Cascades Volcano Observatory in 2015, resuming my work using satellites to track ground deformation, implementing gravity measurements in the region, and generally aiming to better understand the behavior of volcanoes in Washington and Oregon.
In my new role with YVO, I plan to apply the lessons learned over my 15-year USGS career to research in Yellowstone. This past summer, I began working with colleagues from the US and other countries to use gravity as a means of better understanding the nature of the subsurface fluids (gas, water, and magma) that drive seismicity and deformation of the Yellowstone system. This effort continues work begun decades earlier by Bob Smith and co-workers, and is leading me to new collaborations with fellow YVO scientist Jamie Farrell and others at the University of Utah. My interest in magma supply to Hawaiian volcanoes is also relevant to Yellowstone (both are hotspot systems), and I plan to examine a variety of data to investigate how magma is supplied to the reservoir beneath the caldera.
In addition, I hope to continue the expansion of monitoring systems at Yellowstone, augmenting the current network with additional geochemical and geophysical sensors that will help to address such important questions as: What processes drive the frequent earthquake swarms in and around the caldera? What causes abrupt changes in surface deformation over time and space? What is the nature of Yellowstone's magma reservoir?
Relaying information about hazards, especially in collaboration with the National Park Service (including park geologist Jefferson Hungerford and the team at the Yellowstone Center for Resources), will continue to be a priority. Everyone knows of the catastrophic eruptions that have occurred as part of Yellowstone's geologic past, but far more likely to impact the region on human time scales are hydrothermal explosions. Small explosions take place every few years, while a few larger explosions have occurred in the past ~10,000 years, leaving craters that dot portions of the Park's landscape.
I am also optimistic that we can grow our understanding of other volcanic fields in the western United States, including those in Arizona, Utah, New Mexico, and Colorado, over which YVO has operational responsibility.
A particularly attractive aspect of my new job is the opportunity to interact with both the public and other scientists. YVO is unique in that it is a consortium of organizations, including the USGS, Yellowstone National Park, the Universities of Utah and Wyoming, UNAVCO, and the state geological surveys of Wyoming, Montana, and Idaho. The ability to collaborate with scientists of these, and other, institutions is, frankly, a thrilling prospect. No less enticing is the opportunity to share my enthusiasm for Yellowstone, and volcanology in general, with all of you. As my friends and colleagues can no doubt attest (perhaps not without a touch of sarcasm), I enjoy talking. A lot.
With the introduction behind us, time to get to work—there is much to learn! We will do our very best to update the YVO website and USGS Volcanoes Facebook and Twitter feeds with information on the status of ongoing research and interesting geologic activity. In the meantime, I hope to see you around the wonderland that is Yellowstone National Park!
This week I'm stepping down as the Scientist-in-Charge of the Yellowstone Volcano Observatory (YVO). I've held this role since 2002, and it's been an incredibly rewarding 15 years. Recently, I was offered the opportunity to lead the Volcano Disaster Assistance Program (VDAP), where I'll work with my USGS colleagues to assist volcano observatories in developing countries that face daunting volcanic risk. VDAP is a vibrant program created 31 years ago, and is arguably the premier team of volcano scientists on the globe.
It's not without sadness, though, that I will move on from my work at Yellowstone. I've cherished my many visits to the park, starting with trips as a child and young adult, and later, as a geologist. I've worked with outstanding scientists from our YVO partners and indeed from around the world. I've had the incredible good fortune to travel to remote areas around the park to research the variations in gases that can inform our understanding of the subsurface beneath Yellowstone. Our work has gone smoothly, largely due to the staff of Yellowstone National Park, which is incredibly dedicated to ensuring that visitors and researchers alike get the most of their visits and leave Wonderland without incident. For the many Yellowstone lovers out there in the world, I wanted to take a little time to say a proper goodbye, to recount how we got to the present day, and to reflect on some of what's been learned.
Though I'm sad to be moving on, I'm delighted that the observatory will be in excellent hands. Mike Poland will take over as Scientist-in-Charge. Mike has been with the USGS for fifteen years, and is a veteran of both the Cascades and Hawaiian Volcano Observatories. He is an expert in volcano deformation, and in using satellites to track the subtle ups and downs of volcanic terrain that can indicate magma movement below. That's a very useful expertise at Yellowstone, where earthquakes and ground deformation are the dominant monitored signals. Speaking of earthquakes, Jamie Farrell, at the University of Utah has taken over much of the responsibility for the Yellowstone Seismic Network. After many years working with his mentor Bob Smith, Jamie has gained unparalleled experience in studying Yellowstone earthquakes and the deep magma below. In fact, Jamie was responsible for most of the colorful images of the Yellowstone magma reservoir that you've probably seen on the internet. Jefferson Hungerford is the brand new Park Geologist at Yellowstone. His expertise in volcano science, industrious nature, and remarkable good cheer will serve him well as the park focal point for all things geological.
Now a bit of the history…In 2002, during my first weekend as Scientist-in-Charge, the Denali Earthquake struck in Alaska. Surprisingly, when the surface waves hit Yellowstone, some 2000 miles away, it induced hundreds of local earthquakes, many of which were felt around Yellowstone Lake. Fortunately, University of Utah Professor Bob Smith already had worked at Yellowstone for ~30 years and was able to put the activity in context and to help explain the activity to the staff of Yellowstone National Park, to me, and to Hank Heasler, who was also new in his role as the Park Geologist. This notable event threw me "in the deep end," and prepared me for the many earthquake swarms, uplift episodes, and thermal changes that followed over the next decade and a half.
In addition to Bob, I and my colleagues had the good fortune to be mentored by the generation of geologists who did the key research on Yellowstone's geologic past. Bob Christiansen of the USGS spent his summers in the 1960s and 1970s traipsing hill and dale to map out scores of lava flows and ash flow tuffs. He worked with colleagues using K-Ar dating techniques to reveal the age relations of these many events. Chris, as he's known, recognized that there were three massive explosive eruptions at Yellowstone that formed three separate calderas. He published the authoritative geologic map of Yellowstone, and served as the first Scientist-in-Charge of YVO in 2001 until he retired a year later. His contemporaries included the USGS's Ken Pierce, who deciphered much of the glacial history at Yellowstone and with Lisa Morgan traced the older volcanic systems of the Snake River Plain that preceded Yellowstone. Don White and his USGS protégées, Bob Fournier and Patrick Muffler, undertook the ambitious scientific drilling program in Yellowstone's thermal areas, mapping out the temperature and pressure gradients in the subsurface, and collecting core samples of the hydrothermal minerals that we still use as the basis for research projects today. Fournier continued his work at Yellowstone for decades, becoming one of the world's preeminent geochemists. Muffler wrote the first paper on Yellowstone's notorious hydrothermal explosion craters, which represent one of the more common hazards in the park. And of course Bob Smith of the University of Utah, is responsible for a wide swath of geophysical research ranging from Yellowstone earthquakes, to the depth and size of the subsurface magma reservoir, to heat flow and hydrothermal activity beneath Yellowstone Lake. I was incredibly fortunate to be able to learn from all these legends of Yellowstone, and to work with them to further our knowledge of the geologic history, current dynamic behavior, and potential for future activity.
The stage was set by the work of these USGS and academic researchers, as well as by fantastic park geologists such as George Marler, Wayne Hamilton and Rick Hutchinson. Though geologists were well acquainted with the Yellowstone story by the mid 1980s, it was another fifteen years before the public got wind of this amazing story. A 1999 BBC documentary, Supervolcano, interviewed Christiansen, Smith, and others, and captured the imagination of the public. In 2005, BBC and Discovery Channel combined efforts to create a docudrama of the same name. Over the following five years, a series of documentaries thoroughly saturated the market for Yellowstone Volcano, and set the stage for a decade of hyperbole and misinformation with the growth of the internet. One irony of this expansion of the Yellowstone geologic story, is that the work of the pioneering scientists has been lost from the public's mind. Most recent news stories present a simplified, and misunderstood summary of Yellowstone, without any mention of how we got our present knowledge. And the less people know about Yellowstone, or earth science, the more they tend to question the expertise of those who know it best.
Nevertheless, working at Yellowstone has been a tremendous pleasure, and we can take great pride in our accomplishments. Since 2002, we developed a monitoring plan, a hazards assessment, two successive response plans, an exercise to test our response plan, and numerous information statements and web articles to explain ongoing activity such as earthquake swarms and ground uplift. We installed borehole strainmeters and associated downhole seismometers thanks to the Plate Boundary Observatory. We spent almost $1M to expand the seismic and other networks through the American Recovery and Reinvestment Act. We installed miniature, radio-relayed temperature sensors at the Norris Geyser Basin. We expanded the observatory in 2013 to include eight partners, including the geological surveys of the three states that encompass Yellowstone. And we built a website and social media presence that provides detailed explanations of our work and current research efforts. And in our spare time, YVO researchers published well over 50 new research papers in the past 15 years that extend our understanding of the volcanic and hydrothermal system at Yellowstone.
In closing, I want to thank my colleagues for their generosity and friendship over an exceptional fifteen years. Most notable is Peter Cervelli, who has acted as Deputy Scientist-in-Charge for the past five years, but there are many, many others. Together, we've explored the volcano, discovered new phenomena, challenged each other's ideas, and reveled in our good fortune to be able to work at such an amazing place.
Seismic networks locate earthquakes by comparing the arrival times of seismic waves emanating from the earthquake location, or hypocenter. Very small earthquakes (less than a Magnitude 1) cannot be detected on distant seismometers and sometimes even well-located earthquakes may have horizontal and depth uncertainties of more than 0.5 km.
In order to more fully study a 2010 earthquake swarm on the Madison Plateau, in the northwest part of the Yellowstone Caldera, USGS seismologist David Shelly used a specific timeframe of seismic data and mathematical algorithms to detect and relocate tiny earthquakes. Shelly and his colleagues were able to recognize 8710 events, including many small events with magnitude as low as -1. By including these events, Shelly and his colleagues were able to understand more about the relative location of all the earthquakes and how the earthquakes migrated along the crustal fault during the 2010 swarm. The research was published in 2013 in the Journal of Geophysical Research, co-authored with colleagues form the University of Utah. Read more in the web article Taking a closer look at a Yellowstone earthquake swarm.
Natural geysers are rare on Earth; there are fewer than 1,000 worldwide, and about half of them are in Yellowstone National Park. Geysers, whose eruptions range from small bubbling pools, to roaring jets of water and steam that can reach a few hundred meters high, fascinate all who have the good fortune of witnessing one.
In a newly published paper in the "Annual Review of Earth and Planetary Sciences", U. S. Geological Survey hydrologist, Shaul Hurwitz and his coauthor, geology professor Michael Manga at the University of California, Berkeley, synthesize the current state of knowledge about geysers. The authors review past research, and point the way to answering future questions.
Because many of the processes associated with geyser eruptions are similar to those operating in volcanoes, understanding the mechanics of geysers and how they operate can lead to better understanding and predictions of volcanic eruptions.Read the full paper, The Fascinating and Complex Dynamics of Geyser Eruptions online.
Beginning November 7, and lasting two to four weeks, two exciting studies will take place while Yellowstone National Park is in between its summer and winter seasons. They are aimed at learning more about the shallow water system that fuels the famous hot springs, geysers, and other thermal features at Yellowstone. The first is a helicopter-borne electromagnetic study of geothermal areas near the Firehole River, along the Norris-Mammoth corridor, and at the north end of Yellowstone Lake. The second is a seismic study focusing on the area near Old Faithful. The need for these studies are a result of published recommendations from a 2013 scientific committee that formed with the goal to understand ways to reduce human impacts on the park's geothermal features and protect existing park infrastructure from encroachment of hot ground.
The U.S. Geological Survey (USGS), University of Wyoming, and Aarhus University, Denmark, will collaborate to study the groundwater system that feeds the iconic hydrothermal features of Yellowstone National Park. Airborne geophysical electromagnetic (EM) surveys are one of the unique tools that experts can use to examine and map subsurface location, size, shape, salinity and temperature of groundwater. The survey will map important properties of soils and subsurface rocks in order to learn more about Yellowstone's groundwater resources. Because it involves low-level helicopter flights that may disturb park visitors, the research was allowed after roads officially close, and before it opens for winter use.
The University of Utah, in collaboration with the University of Texas El Paso and the National Park Service, will place closely spaced quart-jar-sized, portable seismometers around the Upper Geyser Basin, focusing on the immediate area around Old Faithful Geyser. This is a continuation of a project started in November 2015 when a more general array was deployed for two weeks. The principal objectives of these deployments are to create an image of the shallow seismic velocity structure of the Upper Geyser Basin. The results will help the park service plan for engineering projects relating to developed structures in the area. In addition, data will help scientists better understand the underground fluid flow pathways and hydrothermal properties between geysers and hot springs of the Upper Geyser Basin, including Old Faithful. Importantly, the dense grid of seismometers deployed on the cone of Old Faithful will help us learn more about how the geyser acts before, during, and after eruptions.To learn more about these surveys, download our November 2016 FAQ.
Over the past few years, we've recorded interviews with a number of the scientists who did critical work revealing Yellowstone's volcanic past and present. Our latest installment includes two interviews with Dr. Ken Pierce, a glaciologist and geomorphologist who works today as an emeritus scientists with the USGS in Bozeman, MT. Pierce has written scores of important articles on the geology of Yellowstone, and these two videos give you a flavor of the man and his career.Glaciation in the Greater Yellowstone Area
Interested in supereruptions? This May 2016 talk by USGS scientist Larry Mastin summarizes how we model ash transport after volcanic eruptions, which was applied to some of the big eruptions in Yellowstone's past. The work follows on to Larry's 2014 publication that was summarized as a series of FAQs on our website. The lecture discusses Yellowstone and it's history, but it also discusses the broader study of ash plumes in the atmosphere and how researchers are keen to develop methods to estimate how and where ash will fall after big eruptions.Our website multimedia section hosts a variety of earlier lectures on Yellowstone (about 15 hours worth!).
YVO staff contributed to a new USGS video entitled: "An Illustrated Guide to Reading a Seismogram." This off-beat video provides a short, introductory lesson on how the seismic plots are generated and the potential sources for "signals" on a seismogram.
If you're looking for additional insight on Yellowstone geology, three video interviews were added in September. USGS Video Producer Steve Wessells conducted interviews with some of the key USGS scientists who unlocked the secrets to Yellowstone's volcanic and geothermal history. Bob Christiansen, Patrick Muffler and Bob Fournier reminisce about their early careers working at Yellowstone in the 1960s and 1970s.
The likelihood of a volcanic supereruption from Yellowstone, or any other location on Earth, remains very low in any given year, yet the U.S. Geological Survey is frequently asked about the likely thickness and distribution of ash deposits if Yellowstone were to erupt. This prompted USGS scientists to use a new computer model called Ash3D to simulate the distribution of volcanic ash from a hypothetical large explosive eruption at Yellowstone. A research paper explaining the results was published in Geochemistry, Geophysics, Geosystems on August 27, 2014, and we have developed some FAQ to help explain the background to this study.
The researchers discovered that during very large volcanic eruptions, ash transport is dominated by a rapidly expanding umbrella cloud that results in significant distribution of ash upwind from the volcanic vent. "In essence, the eruption makes its own winds that can overcome the prevailing westerlies that normally dominate weather patterns in the United States," explained USGS geologist Larry Mastin, first author on the manuscript and co-developer of the computer model. "This helps explain the distribution from large Yellowstone eruptions of the past, where considerable amounts of ash reached the west coast." The authors also note that a fraction of an inch or less of ash is likely to be deposited at distances further than 1500 miles, such as on the east and west coasts of the United States. To learn more, please read our Frequently Asked Questions about the model and its application to Yellowstone.
Though we love doing research at YVO, we prefer it when the research is on topics geological rather than the origin of false rumors. Nevertheless, we have received enough concerned emails and phone calls that we've spent some time tracking down a few of the statements made on various "alternative Internet news sources."
1) First, everyone should know that geological activity, including earthquakes and ground uplift/subsidence is well within historical norms and seismicity is actually a bit low at present.
2) Concern over road closures is much overblown. There's been one road closure of a small side road – just over three miles long – that was closed for two days. As one can imagine, it is not easy to maintain roads that pass over thermal areas where ground temperatures can approach those of boiling water. Roads at Yellowstone often need repair because of damage by thermal features as well as extreme cold winter conditions.
3) The park has not been evacuated. This one is pretty easy to verify by everyone. If the Old Faithful webcam shows people, or if news articles are coming out about a hobbyist's remote control helicopter crashing into a hot spring, Yellowstone is certainly open for business.
4) No volcanologists have stated that Yellowstone is likely to erupt this week, this month or this year. In one recent article, a name was attributed to a "senior volcanologist", but that person does not appear to exist, and a geologist with that name assures us that he did not supply any quotes regarding Yellowstone.
5) Finally, we note that those who've kept track of Yellowstone over the past decade or so, have seen a constant stream of "predictions" regarding imminent eruptions at Yellowstone. Many have had specific dates in mind, none had a scientific basis, and none have come true.
We will continue to provide updates on geological activity at Yellowstone, and educational materials to help understand the science around Yellowstone monitoring.
Virtually everything known about Yellowstone's spectacular volcanic past comes from the scientists who work at this observatory, at all our eight member agencies. We're the ones who mapped the deposits, figured out the ages of the eruptions, measured the gases, located the earthquakes, and tracked the ground movement. A few of us have been doing it for over forty years. We will continue to help you understand what's happening at Yellowstone now, and what's likely to happen in the future.
How do we know what's beneath Yellowstone, and how can we image the shallow magma? Seismologists at the University of Utah (a YVO member agency) and the Swiss Federal Institute of Technology undertook a study to image the Yellowstone magma reservoir through a technique called seismic tomography. Using improved methods and data from thousands of earthquakes; they discovered that the magma reservoir is much larger than inferred in previous studies. Read our website article to find out how the study was conducted and what they discovered. The complete results from this new approach are published in the Journal Geophysical Research Letters.
Scientists from the University of Utah – a YVO partner agency – recently presented new research at the Fall meeting of the American Geophysical Union in San Francisco that suggests that the size of the magma body beneath Yellowstone is significantly larger than had been thought. Previous similar studies had underestimated the size of the magma body because of insufficient instrumentation. Over the past decade, improvements to the Yellowstone monitoring network has increased the number and quality of the instruments deployed. This new research takes advantage of these upgrades, which will continue to pay dividends for years to come.
The UU researchers, in collaboration with a scientist from the Swiss Seismological Service in Zurich, used a method called seismic tomography to create an improved image of the magmatic system beneath Yellowstone. One should not think of Yellowstone's magma reservoir as a big cavern full of churning lava. Rather, the reservoir is distributed throughout a porous, sponge-like body of otherwise solid rock, with the amount of liquid rock (melt) varying from place to place. Because seismic waves slow down when traveling through liquids, seismic tomography can be used to map out these variations. The new research shows that while the magma reservoir is bigger than we thought, the proportion of melt to solid rock (estimated at <10-15%) is similar to previous reports and appears to remain way too low for a giant eruption.
Although fascinating, the new findings do not imply increased geologic hazards at Yellowstone, and certainly do not increase the chances of a "supereruption" in the near future. Contrary to some media reports, Yellowstone is not "overdue" for a supereruption. Indeed, it is quite possible that such an eruption will never again occur from the Yellowstone region. Scientist agree that smaller eruptions are likely in the future, but the probability of ANY sort of eruption at Yellowstone still remains very low over the next 10 to 100 years.
YVO scientists from organizations around the country continually monitor geologic conditions at Yellowstone. At present those conditions are normal and there is no heightened concern for public safety. Should conditions change, an established alert system will quickly notify public officials, the general public, and the media. YVO posts regular updates about activity at Yellowstone, which can be found on the activity update webpage. We encourage you to explore our website for additional information on geologic hazards and current activity at Yellowstone.
The YVO webcam is offline temporarily. We hope to get it up and running soon. Please be aware that the camera runs via a solar panel and cellular modem. Unlike most similar cameras, it does not have connection to either AC power or the internet. In the interim, here's a nice image from the camera taken the last week that the camera was operational.
USGS scientist Phil Dawson and colleagues have applied a novel research approach to voice recognition software. In their January 2012 paper, published in Geophysical Research Letters, they utilize this software to discover that background seismic activity in geyser basins can be intimately linked to daily cycles of heating and cooling. For more information read the web article in the Yellowstone volcano earthquake monitoring section.
Recent telemetry problems, from ice and snow buildup on data transmission antennas, have caused intermittent malfunctions of the University of Utah's automated earthquake location system. The malfunctions result in false earthquake reports, which upon review, are then manually deleted from the earthquake catalog. The snow and ice buildup interferes with the continuous streaming of seismic data causing occasional signal dropouts. The dropouts cause spikes to appear in the data streams, which the automated system misinterprets as the abrupt appearance of a high amplitude seismic wave from an earthquake. Windy conditions, common this time of year, exacerbate the problem by contributing additional noise and thereby reducing the overall signal quality of the seismic data streams. In most cases, seismologists at the University of Utah can overcome these problems and still identify and locate earthquakes correctly. Seismic activity at Yellowstone remains at background levels.
More information about errors in the real-time earthquake system that lead to erroneous reports can be found here: Earthquake Hazards Program Errata for Real-time Earthquakes page.
Beginning October 1, 2010, the University of Utah Seismograph Stations has reduced the threshold from M 2.5 to M 1.5 for automated plotting of earthquakes for the Yellowstone region. For more information please see the UUSS announcement. See today's earthquake map.
A report, "Protocols for Geologic Hazards Response by the Yellowstone Volcano Observatory," has just been published. The document summarizes the protocols and tools that the Yellowstone Volcano Observatory (YVO) will now use during earthquakes, hydrothermal explosions, or other geological activity that could lead to a volcanic eruption. This USGS circular was written by an inter-organizational group of scientists, land managers, and emergency responders that met in November 2008 in Bozeman, Montana.
YVO has finished installing a series of radio-equipped temperature sensors to document changes in water flow and heat discharge in the Norris Geyser Basin. Daily, weekly, and monthly temperature plots are now available from our new monitoring page, "Taking the Temperature of the Norris Geyser Basin."
Geysers are rare hot springs that periodically erupt bursts of steam and hot water. Yellowstone National Park has more than half of the world's geysers. Old Faithful has remained faithful for at least the past 135 years, showering appreciative tourists every 50 to 95 minutes (most recently an annual average of 91 minutes). To view Old Faithful in real-time, see the National Park Service Old Faithful Webcam.
There were were notable changes in thermal activity at Norris Geyser Basin in 2003. These changes resulted in the closure of the Back Basin Trail and temporarydeployment of a monitoring network by YVO. Learn more.