USGS Volcano Notice - DOI-USGS-CALVO-2021-12-27T10:39:07-08:00

CALIFORNIA VOLCANO OBSERVATORY WEEKLY UPDATE
U.S. Geological Survey
Tuesday, December 28, 2021, 9:18 AM PST (Tuesday, December 28, 2021, 17:18 UTC)

Monitored CALIFORNIA VOLCANOES
Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN

Activity Update: All volcanoes monitored by CalVO using telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Volcanoes monitored include Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Volcanic Region, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.

Observations for December 20, 2021 (0000h PST) through December 26, 2021 (2359h PST):

Clear Lake Volcanic Field: One earthquake at or above M1.0 was detected, measuring M1.8. As is typical, moderate levels of seismicity were recorded at the Geysers geothermal steam field south of the Clear Lake Volcanic Field; 50 earthquakes at or above M1.0 were detected, with the largest measuring M2.6.
Lassen Volcanic Center: No earthquakes at or above M1.0 were detected.
Long Valley Volcanic Region: No earthquakes at or above M1.0 were detected in the Long Valley Caldera. No earthquakes at or above M1.0 were detected in the Mono-Inyo Craters. Two earthquakes at or above M1.0 were detected at Mammoth Mountain, with the largest measuring M2.4. No earthquakes at or above M1.0 were detected south of the caldera in the Sierra Nevada range.
Mount Shasta: No earthquakes at or above M1.0 were detected.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Salton Buttes: Two earthquakes at or above M1.0 were detected, with the largest measuring M1.6.
Coso Volcanic Field: Thirty-three earthquakes at or above M1.0 were detected with the largest measuring M2.7.
Ubehebe Craters: No earthquakes at or above M1.0 were detected.

These earthquake counts are preliminary and subject to change as the earthquakes are reviewed by seismologists. The U.S. Geological Survey will continue to monitor these volcanoes closely and will issue additional updates and changes in alert level as warranted. For a definition of alert levels see http://volcanoes.usgs.gov/activity/alertsystem/icons.php.

As part of the U.S. Geological Survey's Volcano Hazards Program, the California Volcano Observatory monitors the volcanoes of California and Nevada and advances scientific understanding of volcanic processes in order to reduce the harmful impacts of volcanic activity. For additional USGS CalVO volcano information, background, images, and other graphics visit http://volcanoes.usgs.gov/observatories/calvo/. For general information on the USGS Volcano Hazard Program visit http://volcanoes.usgs.gov. Statewide seismic information for California and Nevada can be found at https://earthquake.usgs.gov/earthquakes/map/.



CONTACT INFORMATION:

askCalVO@usgs.gov