Hazard Notification System (HANS) for Volcanoes


U.S. Geological Survey
Thursday, July 11, 2019, 4:36 PM PDT (Thursday, July 11, 2019, 23:36 UTC)

36°1'48" N 117°49'12" W, Summit Elevation 7874 ft (2400 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

The California Volcano Observatory detects neither significant change to the volcanic system beneath Coso Volcanic Field, Inyo County, California, nor impending volcanic activity, following the Ridgecrest earthquakes. The seismic swarm activity continues within the volcanic field, but as of the time of this announcement, intensity of the seismic swarm is declining. The Coso geothermal field contained within the Coso Volcanic Field overall has not experienced heightened levels of seismicity when compared with previous swarms.

The current activity at Coso can be considered distant aftershocks, or triggered earthquakes. The M7.1 on July 5 occurred on a NW-trending fault oriented toward the Coso area, and it is common for large earthquakes to cause aftershocks beyond the actual fault rupture. The California Volcano Observatory will continue to monitor the situation for any sign of volcanic activity and provide updates as warranted.

Where to go for additional information:

Background on Coso Volcanic Field
Latitude: 36.03° N
Longitude: 117.82° W
The Coso Volcanic Field is located on the eastern side of the Sierra Nevada mountains at the northern end of the Mojave Desert, about 64 km (~40 miles) north of Ridgecrest. The field covers about 150 square miles primarily within the Naval Air Weapons Station at China Lake, and is comprised of lava domes, lava flows, and cinder cones erupted over the past 250,000 years. The most recent eruption was about 40,000 years ago.

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 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. 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 http://volcanoes.usgs.gov. Statewide seismic information for California and Nevada can be found at http://earthquake.usgs.gov/earthquakes/recenteqscanv/.