Postcards from the Field
During the summer months, scientists from the Volcano Hazards Program lead educational field trips, conduct extensive field surveys, and install monitoring equipment at various volcanoes. These activities help scientists and educators understand volcanic processes. Below is a compilation of "Postcards from the Field" collected during the summer field seasons.
TDEM Aerial Geophysical Survey at Mount St. Helens (WA) September 14, 2011
Suspended 100 feet below the helicopter, a hexagonal-shaped Time Domain Electromagnetic and Magnetic (TDEM) survey instrument collects and records geophysical measurements along the eastern flank of Mount St. Helens. TDEM is an exploration technique in which electric currents are induced in the Earth and the corresponding magnetic field response is measured. The data will be used to map the presence of hydrothermally-altered and water-saturated rocks within the volcano. This analysis is part of an ongoing research program to identify the slip surface of the massive landslide that triggered the historic 1980 eruption. The mapping may also provide information about water-bearing layers that increase the likelihood of future large landslides. Read the full article in Nature to learn more about this research. Postcard photo by Liz Westby.
Final Monitoring Station Installation at Newberry National Volcanic Monument (OR) August 16, 2011
Inside the brown fiberglass hut, USGS Field Engineer Martin LaFevers connects the seismometer and Global Positioning System (GPS) to a power supply in preparation for the transmission of seismic and GPS data in near real-time. Newberry has been identified by the USGS as a very high threat volcano owing to a large adjacent population around Bend, and its long history of eruptive activity. The most recent eruption 1,300 years ago produced the Big Obsidian Flow in Newberry Caldera (pictured to left, over hill south of lake). With adequate instrumentation in a monitoring network, the USGS can provide rapid and reliable information about volcanic unrest, and forecasts and warnings of potential volcanic eruptions. Read more about Newberry volcano at the Cascades Volcano Observatory website. Postcard photo by Liz Westby.
GPS Tracks Ground Deformation at Newberry National Volcanic Monument (OR) August 16, 2011
USGS Field Engineer Ben Pauk records site and equipment information for the Global Positioning System (GPS) installed at the North Rim station in the Newberry National Volcanic Monument. The GPS records the precise position of the station, including latitude, longitude and elevation. Tracking subtle ground deformation through GPS provides insight into how volcanoes can change over time in response to changes in the magmatic system deep beneath the volcano, or in response to regional tectonic stresses. Read more about the use of GPS to monitor volcanoes from the USGS Earthquake Hazards Program website. Postcard photo by Liz Westby.
Tracking Subsurface Water at Mount St. Helens (WA) September 6, 2011
Jeff Wynn, Herb Pierce and Chris Lockett (R to L) observe the incoming data used to measure water conductivity in the deep (900+ m) subsurface at Mount St. Helens. Water, from rain, melting snow and ice, seeps into the rubble of the crater floor. The water fills the pore spaces and interacts with still hot lava to become strongly acidic. This study uses Controlled-Source-Audio-Magnetotellurics (CSAMT) to follow the trail of the highly conductive subsurface water. These types of baseline measurements are invaluable for determining how rock can be weakened by water saturation and hydrothermal alteration. Read our web article to learn more about how scientists study volcanoes. Postcard photo by Liz Westby.
Mapping Glacial Advance at Mount St. Helens (WA) June 28, 2011
A geologist finishes field notes after mapping the extent of Crater Glacier at Mount St. Helens. Crater Glacier, formed by the accumulation of snow and rocks falling from the inside of the crater rim and walls, began to deform and flow in 1996. Over the past five years, Crater Glacier's terminus has been advancing at about 30 cm per day. Mapping the glacier's extent and volume are important for assessing lahar hazards. Should the glacial ice and snow be melted swiftly by a future dome-building eruption, a torrent of glacial meltwater could produce a fast-moving flood of water and debris that pours onto the Pumice Plain and possibly down the North Fork Toutle River. Read the publication documenting the evolution of Crater Glacier during recent dome-building events. Postcard photo by A.T. Barsotti.
Studying Volcaniclastic Deposits Northern Patagonia, Chile, March 2011
USGS research hydrologist Tom Pierson, working with geologists from SERNAGEOMIN (Chile's geological survey), examines lahar and volcanic flood deposits along Rio Chaitén, approximately 8 km downstream of Chaitén volcano. The rhyolite volcano's current eruptive phase began in May, 2008, producing several pyroclastic flows and widespread ashfall. Lahars and sediment-rich floods were triggered by the first few centimeters of post-eruption rainfall, sweeping down the steep ash-covered slopes of the volcano, completely filling the original course of the Chaitén River, before flooding and burying Chaitén town (10 km from the volcano) in sediment. By studying these deposits and interpreting how sediments are mobilized and emplaced during and following eruptions, scientists are gaining a better understanding of how volcanoes can trigger life-threatening volcano-hydrologic hazards downstream of active volcanoes. For more information read about the Volcano Disaster Assistance Program's response in Chile. Postcard photo by Carolina Silva.
Science Teachers Explore Mount Rainier (WA) July 18-22, 2011
Members of the USGS Cascades Volcano Observatory and National Park Service provide a week-long opportunity for teachers to explore Mount Rainier National Park conducting inquiry-based volcano science activities. Here, teachers measure and record the amount of snow that melts over a one-hour period to gain insight into summer ablation rates of snow fields at 5,400 feet in elevation. The workshop curriculum and educator's guide, which includes more than 30 activities and a field guide to geological sites of interest at Mount Rainier National Park, is designed for middle school students with adaptations and extensions that offer learning opportunities for students in higher and lower grade levels. Download the complete Living with a Volcano in your Backyard educators guide. Postcard photo by C. Driedger.
Collecting Volcanic Gas Samples on Mount Hood (OR) July 9, 2011
Steven Ingebritsen (lower right, in blue hat) kneels in the warm mud as he collects samples of the gases emitted from the fumaroles on the north side of Crater Rock on Mount Hood. The samples are taken back to the laboratory for an analysis of the gases' chemical composition. 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. Although Mount Hood is not currently in a state of eruption, it remains an active volcano. Visit the Volcano Emission Project's website to learn more. Postcard photo by Christoph Kern.
Volcanic Gas Sampling on Mount St. Helens (WA) July 6, 2011
Christoph Kern acquires ultraviolet images of volcanic gas over the dome and crater of Mount St. Helens. Although practically invisible to the human eye, sulfur dioxide absorbs ultraviolet light and appears dark in images captured by the equipment. Sulfur dioxide is typically emitted from magma as it approaches the surface, so surveys are conducted on a regular basis at Mount St. Helens and other Cascades volcanoes to determine if magma is on the move. Sulfur dioxide was not detectable during this particular measurement. Visit the Volcano Emission Project's website to learn more. Postcard photo by Cynthia Werner.
