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California Volcano Observatory images.
Simplified geologic map (left) and diagrammatic cross section (right) of Long Valley Caldera. The resurgent dome, Doe Ridge, Mammoth Mountain, and the Inyo Craters and Domes all reflect volcanic activity since 760,000 years ago, when a giant eruption formed the caldera.
Simplified geologic map (left) and diagrammatic cross section (right) of Long Valley Caldera. The resurgent dome, Doe Ridge, Mammoth Mountain, and the Inyo Craters and Domes all reflect volcanic activity since 760,000 years ago, when a giant eruption formed the caldera.
High-resolution, bare-earth, airborne light detection and ranging (LiDAR) image, looking obliquely northwest into Rocky Ridge.
High-resolution, bare-earth, airborne light detection and ranging (LiDAR) image, looking obliquely northwest into Rocky Ridge.
Mount Shasta, a steep-sided Cascade Range stratovolcano in Northern California, looms above Little Glass Mountain, a thick obsidian flow erupted from the Medicine Lake shield volcano about 1,000 years ago. These are just two of the young volcanic areas monitored by the USGS California Volcano Observatory. USGS photo.
Mount Shasta, a steep-sided Cascade Range stratovolcano in Northern California, looms above Little Glass Mountain, a thick obsidian flow erupted from the Medicine Lake shield volcano about 1,000 years ago. These are just two of the young volcanic areas monitored by the USGS California Volcano Observatory. USGS photo.
Microprobe laboratory in Menlo Park, California.
Argon geochronology lab in Menlo Park, California.
Argon geochronology lab in Menlo Park, California.
Medicine Lake, California simplified hazards map showing potential impact area for ground-based hazards during a volcanic event.
Medicine Lake, California simplified hazards map showing potential impact area for ground-based hazards during a volcanic event.
Map showing distribution of Long Valley postcaldera rhyolites. Abbreviations: CD, Casa Diablo geothermal plant; Ski area, Mammoth Mountain Ski Area; LVEW, Long Valley Exploratory Well, 3 km deep, located high on resurgent uplift; s, surficial deposits filling structural lows on resurgent uplift.
Map showing distribution of Long Valley postcaldera rhyolites. Abbreviations: CD, Casa Diablo geothermal plant; Ski area, Mammoth Mountain Ski Area; LVEW, Long Valley Exploratory Well, 3 km deep, located high on resurgent uplift; s, surficial deposits filling structural lows on resurgent uplift.
Example Hydrotherm output. Hydrotherm is a three-dimensional simulation of multiphase groundwater flow and heat transport in the temperature range of 0 to 1200 degrees Celsius and the pressure range of 1 to 1000 MPa.
Example Hydrotherm output. Hydrotherm is a three-dimensional simulation of multiphase groundwater flow and heat transport in the temperature range of 0 to 1200 degrees Celsius and the pressure range of 1 to 1000 MPa.
Inverted funnel connected to thermoplastic tubing used to collect gas from a hot spring pool near Lassen Peak, California.
Inverted funnel connected to thermoplastic tubing used to collect gas from a hot spring pool near Lassen Peak, California.
The photo shows several silica-rich lava domes in the Coso Volcanic Field, the closest of which erupted onto the desert floor around 80,000 years ago. USGS photo by Seth Burgess.
The photo shows several silica-rich lava domes in the Coso Volcanic Field, the closest of which erupted onto the desert floor around 80,000 years ago. USGS photo by Seth Burgess.
Flow banding of Panum pumice and obsidian of the same composition.
Flow banding of Panum pumice and obsidian of the same composition.
A mud pot releases a burst of gas in the Davis-Schrimpf Seep Field near the Salton Sea. The geothermal area here is related to the same faulting and volcanic system which created the Salton Buttes lava domes. USGS photo by Deb Bergfeld, 2016.
A mud pot releases a burst of gas in the Davis-Schrimpf Seep Field near the Salton Sea. The geothermal area here is related to the same faulting and volcanic system which created the Salton Buttes lava domes. USGS photo by Deb Bergfeld, 2016.
Drew Downs in Iceland with a glacier in hte background.
Drew Downs in Iceland with a glacier in hte background.
Main hydrothermal features of the new (2016) 3-D model of the subsurface at Long Valley Caldera. This schematic is based on a survey of the electrical properties of the earth (magnetotellurics) below. Arrows show subsurface water flow, with colors keyed to changing water temperature, from blue (cold) to red (hot). Purple arrows show an extinct hot water pathway.
Main hydrothermal features of the new (2016) 3-D model of the subsurface at Long Valley Caldera. This schematic is based on a survey of the electrical properties of the earth (magnetotellurics) below. Arrows show subsurface water flow, with colors keyed to changing water temperature, from blue (cold) to red (hot). Purple arrows show an extinct hot water pathway.
The photo was taken from a vantage looking up Avalanche Gulch at Red Banks (a line of cliffs along the ridge central to the photograph).
The photo was taken from a vantage looking up Avalanche Gulch at Red Banks (a line of cliffs along the ridge central to the photograph).
The USGS Bay Area offices are located in Building 19 at Moffett Field, part of the NASA Ames Research Center
The USGS Bay Area offices are located in Building 19 at Moffett Field, part of the NASA Ames Research Center
This is a simplified diagram of regional range front faults as they intersect the Long Valley Caldera.
This is a simplified diagram of regional range front faults as they intersect the Long Valley Caldera.
CalVO's Stuart Wilkinson skis out to a remote seismic instrument in the Long Valley volcanic region to perform routine maintenance.
CalVO's Stuart Wilkinson skis out to a remote seismic instrument in the Long Valley volcanic region to perform routine maintenance.
Geologic field-trip guide to Lassen Volcanic National Park and vicinity, California
Geologic field-trip guide to Lassen Volcanic National Park and vicinity, California
Cliffs of Franciscan Complex rocks near the Point Bonita Lighthouse reveal metamorphosed pillow lava at their bases. USGS photo by Jessica L. Ball
Cliffs of Franciscan Complex rocks near the Point Bonita Lighthouse reveal metamorphosed pillow lava at their bases. USGS photo by Jessica L. Ball
In this view down from the Point Bonita lighthouse, a sea arch made up of slightly metamorphosed pillow basalts rises from the surf. The green tinge on some of the "pillows" is the result of metamorphism, replacing primary minerals with greener ones such as chlorite and epidote. USGS photo by Jessica L. Ball
In this view down from the Point Bonita lighthouse, a sea arch made up of slightly metamorphosed pillow basalts rises from the surf. The green tinge on some of the "pillows" is the result of metamorphism, replacing primary minerals with greener ones such as chlorite and epidote. USGS photo by Jessica L. Ball