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.