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# California Volcano Observatory

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As a part of the U.S. Geological Survey's Volcano Hazards Program, the California Volcano Observatory aims to advance scientific understanding of volcanic processes and lessen the harmful impacts of volcanic activity in the volcanically active areas of California and Nevada. 

### Young Volcanoes in California & Nevada

**Very High Threat Potential** 1Lassen Volcanic CenterLong Valley CalderaMount Shasta**High Threat Potential** 1Clear Lake Volcanic FieldMedicine LakeMono-Inyo ChainSalton Buttes**Moderate Threat Potential** 1Coso Volcanic FieldMammoth MountainMono Lake Volcanic FieldSoda Lakes (NV)Ubehebe Craters1. View the threat rankings of US Volcanoes.

### California's Volcanic Hazards Geonarrative

GIS-based interactive website guides you through the eight young volcanic areas within California that pose the highest threat. 

Explore Volcanic Hazard Exposure

### Volcano Research Laboratories

CalVO hosts several laboratories for multidisciplinary research of geologic phenomena. 

Learn About the Labs

### CalVO Quick Links

                        - CalVO News
                        - Latest status update
                        - Subscribe to Volcano Notification Service - emailed updates
                        - California's volcanic hazards
                        - California volcano hazard assessments

The U.S. Geological Survey California Volcano Observatory (USGS CalVO) was formed in 2012 and is headquartered in Menlo Park and Moffett Field, CA. It replaced the former Long Valley Observatory (LVO), which was established in 1982 to monitor the restless Long Valley Caldera and Mono-Inyo Craters region of Eastern California. CalVO now monitors these and other potentially hazardous volcanoes in California and Nevada to help communities and government authorities understand, prepare for, and respond to, volcanic activity. 

Sixteen young volcanoes designated as Low Threat to Very High Threat are dispersed throughout the State. Partially molten rock (magma) resides beneath at least seven of these—Medicine Lake Volcano, Mount Shasta, Lassen Volcanic Center, Clear Lake Volcanic Field, the Long Valley Volcanic Region, Coso Volcanic Field, and Salton Buttes— producing volcanic earthquakes(seismicity), toxic gas emissions, hot springs, and (or) ground movement (deformation).

## News

How hot is Long Valley Caldera?

April 2, 2024

####   How hot is Long Valley Caldera?

One schist, two schist, greenschist, blueschist: Metamorphosed volcanic rocks in California

March 20, 2024

####   One schist, two schist, greenschist, blueschist: Metamorphosed volcanic rocks in California

Mud pot, mud seep, or mud volcano?

March 6, 2024

####   Mud pot, mud seep, or mud volcano?

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## Publications

September 24, 2021

####                 Multidisciplinary constraints on magma compressibility, the pre-eruptive exsolved volatile fraction, and the H2O/CO2 molar ratio for the 2006 Augustine eruption, Alaska              

Volcano Hazards Program, Volcano Science Center, California Volcano Observatory

February 25, 2019

####                 California’s exposure to volcanic hazards              

The potential for damaging earthquakes, landslides, floods, tsunamis, and wildfires is widely recognized in California. The same cannot be said for volcanic eruptions, despite the fact that they occur in the state about as frequently as the largest earthquakes on the San Andreas Fault. At least ten eruptions have taken place in the past 1,000 years, and future volcanic eruptions are inevitable.The

Volcano Hazards Program, Volcano Science Center, California Volcano Observatory, Clear Lake Volcanic Field, Coso Volcanic Field, Lassen Volcanic Center, Long Valley Caldera, Mammoth Mountain, Medicine Lake, Mono Lake Volcanic Field, Mono-Inyo Craters, Mount Shasta, Salton Buttes, Soda Lakes, Ubehebe Craters

October 3, 2012

####                 Lahar hazard zones for eruption-generated lahars in the Lassen Volcanic Center, California              

Natural Hazards Mission Area, Volcano Hazards Program, Volcano Science Center, California Volcano Observatory

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## Science

link

December 7, 2023

####                 Volcano Hazards Assessments              

California Volcano Observatory

link

December 7, 2023

####   Volcano Hazards Assessments

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link

December 7, 2023

####                 Volcano Monitoring at California Volcano Observatory              

California Volcano Observatory

link

December 7, 2023

####   Volcano Monitoring at California Volcano Observatory

Learn More

link

December 7, 2023

####                 California has active and hazardous volcanoes              

California Volcano Observatory

link

December 7, 2023

####   California has active and hazardous volcanoes

Learn More

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## Multimedia

Large spherulites in Hot Creek rhyolite lava in the Long Valley Caldera

Panoramic view of the Long Valley Caldera from its north side

CalVO geologists take paleomag samples from a basaltic andesite lava flow on Ash Creek Butte

A digital elevation map of Yellowstone Caldera

Mount Konocti as seen from the town of Clear Lake.

Thurston Lake and Mount Konocti, Clear Lake Volcanic Field

Mammoth Mountain

Eddy covariance station at Mammoth Mountain, California

Rear-arc basalt lava outcrop

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### Young Volcanoes in California & Nevada

**Very High Threat Potential** 1Lassen Volcanic CenterLong Valley CalderaMount Shasta**High Threat Potential** 1Clear Lake Volcanic FieldMedicine LakeMono-Inyo ChainSalton Buttes**Moderate Threat Potential** 1Coso Volcanic FieldMammoth MountainMono Lake Volcanic FieldSoda Lakes (NV)Ubehebe Craters1. View the threat rankings of US Volcanoes.

### Volcanoes Hazards Program Links

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