This aerial photo, taken from about 40,000 feet and looking east, highlights the rugged central lava domes and smooth circular debris apron of the Sutter Buttes. USGS photo by J. Ball.
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Sutter Buttes, California seen from the air
This aerial photo, taken from about 40,000 feet and looking east, highlights the rugged central lava domes and smooth circular debris apron of the Sutter Buttes. USGS photo by J. Ball.
Taking water table elevation measurements in the Long Valley Caldera, California
Taking water table elevation measurements in the Long Valley Caldera, CaliforniaA USGS scientist pulls a conductivity sensor out of a water well. These wells are usually drilled for other purposes (like livestock or agriculture) but are useful for scientists doing geodetic surveys. USGS photo by J. Crozier.
Taking water table elevation measurements in the Long Valley Caldera, California
Taking water table elevation measurements in the Long Valley Caldera, CaliforniaA USGS scientist pulls a conductivity sensor out of a water well. These wells are usually drilled for other purposes (like livestock or agriculture) but are useful for scientists doing geodetic surveys. USGS photo by J. Crozier.
A gravimeter taking measurements in Long Valley, California
A gravimeter taking measurements in Long Valley, CaliforniaGravimeters, or "gravity meters", measure the strength of the Earth's gravitational field at any given point. This value may be affected by ground elevation, the density of the rock or material on which the gravimeter sits, and the presence of magma or fluids beneath the Earth's surface. USGS photo by J. Crozier.
A gravimeter taking measurements in Long Valley, California
A gravimeter taking measurements in Long Valley, CaliforniaGravimeters, or "gravity meters", measure the strength of the Earth's gravitational field at any given point. This value may be affected by ground elevation, the density of the rock or material on which the gravimeter sits, and the presence of magma or fluids beneath the Earth's surface. USGS photo by J. Crozier.
Comparison of caldera-forming eruption sizes in the USA
Comparison of caldera-forming eruption sizes in the USAComparison of caldera-forming eruption sizes (by volume of erupted magma) in the U.S., modified from an AVO/USGS figure. Also included for reference is the 1980 eruption of Mount St. Helens. The three caldera-forming eruptions in Alaska are more than 200 times the size of the 1980 eruption of Mount St.
Comparison of caldera-forming eruption sizes in the USA
Comparison of caldera-forming eruption sizes in the USAComparison of caldera-forming eruption sizes (by volume of erupted magma) in the U.S., modified from an AVO/USGS figure. Also included for reference is the 1980 eruption of Mount St. Helens. The three caldera-forming eruptions in Alaska are more than 200 times the size of the 1980 eruption of Mount St.
Lahar Safety Infographic
A lahar is a volcanic mudflow. Learn if you are if you are in a lahar hazard zone and how to evacuate to high ground. If you are in a lahar hazard zone and get a lahar alert - go now! Every second matters.
A lahar is a volcanic mudflow. Learn if you are if you are in a lahar hazard zone and how to evacuate to high ground. If you are in a lahar hazard zone and get a lahar alert - go now! Every second matters.
2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA
2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CAAn eruption of the tabletop "Mount Shasta" using cornstarch as volcanic ash and puffed rice cereal as "lava bombs". USGS photo by M. Glasgow.
2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CA
2026 Pacific Islanders Encouraging Fun, Science & Technology (PIEFEST) in San Mateo, CAAn eruption of the tabletop "Mount Shasta" using cornstarch as volcanic ash and puffed rice cereal as "lava bombs". USGS photo by M. Glasgow.