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 November 1, 2015 (0000h PST) through November 30, 2015 (2359h PDT):
Mt Shasta: One M1 or greater earthquake was detected (M1.29).
Medicine Lake: Ten M1.0 or greater earthquakes were detected, with the largest registering M1.76. These earthquakes occurred during a minor seismic swarm on November 12-13 near the Siskiyou-Modoc county line about 4 miles east-northeast of Medicine Lake.
Lassen Volcanic Center: No earthquakes of M1.0 or greater were detected.
Clear Lake Volcanic Field: Three earthquakes of M1.0 or greater were detected. The largest event registered M2.21. [Note: The typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M2.78].
Long Valley Volcanic Region: In Long Valley Caldera, 17 earthquakes of M1.0 or greater were detected. The largest event registered M2.00. In the Mono Craters region, 1 earthquake of M1.0 or greater was detected and registered M1.37. One earthquake of M1.0 or greater was detected under Mammoth Mountain (M2.03). [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.60].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Three earthquakes of M1.0 or greater were detected. The largest registered M1.75.
Coso Volcanic Field: The typical high level of seismicity was observed, with 19 earthquakes M1.0 or greater. The largest registered M2.65.
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.
December 09, 2015. California Volcanoes , United – States :
Current Volcano Alert Level: all NORMAL
Current Aviation Color Code: all GREEN
Source : Calvo/Usgs
Photo : marlimillerphoto.com