Link to USGS home page.
USGS HOME
Contact USGS

  • Assess
  • Prepare
  • Forecast
  • |
  • Activity
  • Products
  • Observatories
  • About


Activity Updates

Choose Activity Updates: | | | | | | | | | | | |

CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Thursday, June 1, 2017, 2:37 PM PDT (Thursday, June 1, 2017, 21:37 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 May 1, 2017 (0000h PST) through May 31, 2017 (2359h PDT):
Mt Shasta: Six earthquakes of M1.0 or greater were detected, with the largest registering M2.71.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: No earthquakes at or above M1.0 were detected.
Clear Lake Volcanic Field: Three earthquakes of M1.0 or greater were detected, with the largest registering M1.20. [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 M2.90].
Long Valley Volcanic Region: In Long Valley Caldera, 10 earthquakes of M1.0 or greater were detected, with the largest event registering M2.04. No earthquakes at or above M1.0 were detected in the Mono Craters region. No earthquakes at or above M1.0 were detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.21].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Nine earthquakes of M1.0 or greater were detected, with the largest registering M2.72.
Coso Volcanic Field: The typical high level of seismicity was observed, with 23 earthquakes M1.0 or greater. The largest registered M2.09.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Monday, May 1, 2017, 9:33 AM PDT (Monday, May 1, 2017, 16:33 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 April1, 2017 (0000h PST) through April 30, 2017 (2359h PDT):
Mt Shasta: Two earthquakes of M1.0 or greater were detected, with the largest registering M1.25.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: No earthquakes at or above M1.0 were detected.
Clear Lake Volcanic Field: Three earthquakes of M1.0 or greater were detected, with the largest registering M1.74. [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 M3.73].
Long Valley Volcanic Region: In Long Valley Caldera, 28 earthquakes of M1.0 or greater were detected, with the largest event registering M2.80. No earthquakes at or above M1.0 were detected in the Mono Craters region. No earthquakes at or above M1.0 were detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.50].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Five earthquakes of M1.0 or greater were detected, with the largest registering M1.56.
Coso Volcanic Field: The typical high level of seismicity was observed, with 9 earthquakes M1.0 or greater. The largest registered M1.43.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Monday, April 3, 2017, 10:28 AM PDT (Monday, April 3, 2017, 17:28 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 March 1, 2017 (0000h PST) through March 31, 2017 (2359h PDT):
Mt Shasta: No earthquakes at or above M1.0 were detected.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: One earthquake at or above M1.0 was detected (M1.72).
Clear Lake Volcanic Field: No earthquakes at or above M1.0 were detected. [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, 7 earthquakes of M1.0 or greater were detected, with the largest event registering M2.20. One earthquake at or above M1.0 was detected in the Mono Craters region (M1.60). One earthquake at or above M1.0 was detected under Mammoth Mountain, registering M2.77. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.40].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Thirty earthquakes of M1.0 or greater were detected, with the largest registering M3.09.
Coso Volcanic Field: The typical high level of seismicity was observed, with 20 earthquakes M1.0 or greater. The largest registered M2.32.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Thursday, March 2, 2017, 11:00 AM PST (Thursday, March 2, 2017, 19:00 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 February 1, 2017 (0000h PST) through February 28, 2017 (2359h PDT):
Mt Shasta: Two earthquakes at or above M1.0 were detected, with the largest registering M2.50.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: No earthquakes at or above M1.0 were detected.
Clear Lake Volcanic Field: Two earthquakes at or above M1.0 were detected, with the largest registering M1.42. [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 M4.16].
Long Valley Volcanic Region: In Long Valley Caldera, 14 earthquakes of M1.0 or greater were detected, with the largest event registering M2.34. One earthquake at or above M1.0 was detected in the Mono Craters region (M2.09). Three earthquakes at or above M1.0 were detected under Mammoth Mountain, with the largest registering M1.30. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.28].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Eight earthquakes of M1.0 or greater were detected, with the largest registering M1.59.
Coso Volcanic Field: The typical high level of seismicity was observed, with 14 earthquakes M1.0 or greater. The largest registered M1.70.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Wednesday, February 1, 2017, 9:59 AM PST (Wednesday, February 1, 2017, 17:59 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 January 1, 2017 (0000h PST) through January 31, 2017 (2359h PDT):
Mt Shasta: No earthquakes at or above M1.0 were detected.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: Eight earthquakes at or above M1.0 were detected. The largest event registered M2.12.
Clear Lake Volcanic Field: Five earthquakes at or above M1.0 were detected, with the largest registering M2.26. [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 M3.89].
Long Valley Volcanic Region: In Long Valley Caldera, 46 earthquakes of M1.0 or greater were detected, with the largest event registering M2.12. Four earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M2.08. No earthquakes at or above M1.0 were detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M3.44].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Six earthquakes of M1.0 or greater were detected, with the largest registering M1.96
Coso Volcanic Field: The typical high level of seismicity was observed, with 28 earthquakes M1.0 or greater. The largest registered M2.67.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Wednesday, January 4, 2017, 1:46 PM PST (Wednesday, January 4, 2017, 21:46 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 1, 2016 (0000h PST) through December 31, 2016 (2359h PDT):
Mt Shasta: One earthquake at or above M1.0 was detected (M1.46).
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: No earthquakes at or above M1.0 were detected.
Clear Lake Volcanic Field: One earthquake at or above M1.0 was detected (M1.74). [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 M2.58].
Long Valley Volcanic Region: In Long Valley Caldera, 174 earthquakes of M1.0 or greater were detected, with the largest event registering M3.99. Many of these events occurred during a minor seismic swarm on December 13-14, 2016 about 2.5 miles east-southeast of the town of Mammoth Lakes. Three earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M1.75. No earthquakes at or above M1.0 were detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.79].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Thirteen earthquakes of M1.0 or greater were detected, with the largest registering M1.67.
Coso Volcanic Field: The typical high level of seismicity was observed, with 23 earthquakes M1.0 or greater. The largest registered M2.39.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Thursday, December 1, 2016, 9:27 AM PST (Thursday, December 1, 2016, 17:27 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 November 1, 2016 (0000h PST) through November 30, 2016 (2359h PDT):
Mt Shasta: One earthquake at or above M1.0 was detected (M2.37).
Medicine Lake: One earthquake at or above M1.0 was detected (M1.07).
Lassen Volcanic Center: Five earthquakes at or above M1.0 were detected, with the largest registering M1.49.
Clear Lake Volcanic Field: No earthquakes at or above M1.0 were detected. [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 M3.33].
Long Valley Volcanic Region: In Long Valley Caldera, 12 earthquakes of M1.0 or greater were detected, with the largest event registering M2.86. Three earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M1.63. No earthquakes at or above M1.0 were detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M2.83].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Forty earthquakes of M1.0 or greater were detected, with the largest registering M2.95. Many of these events occurred during a minor seismic swarm on November 15, 2016 about 6 miles northwest of the town of Calipatria.
Coso Volcanic Field: The typical high level of seismicity was observed, with 28 earthquakes M1.0 or greater. The largest registered M2.87.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Tuesday, November 1, 2016, 9:56 AM PDT (Tuesday, November 1, 2016, 16:56 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 October 1, 2016 (0000h PST) through October 31, 2016 (2359h PDT):
Mt Shasta: One earthquake at or above M1.0 was detected (M1.29).
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: One earthquake at or above M1.0 was detected (M1.62).
Clear Lake Volcanic Field: Three earthquakes at or above M1.0 were detected, with the largest registering M1.23. [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 M3.31].
Long Valley Volcanic Region: In Long Valley Caldera, 20 earthquakes of M1.0 or greater were detected, with the largest event registering M2.45. Three earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M2.76. Three earthquakes at or above M1.0 were detected under Mammoth Mountain. The largest was M1.31. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M3.16].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Thirty-four earthquakes of M1.0 or greater were detected, with the largest registering M3.02. Many of these events occurred during two minor seismic swarms on October 26-27 and 31, 2016 about 5 miles northwest of the town of Calipatria.
Coso Volcanic Field: The typical high level of seismicity was observed, with 23 earthquakes M1.0 or greater. The largest registered M2.47.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Tuesday, October 11, 2016, 12:15 PM PDT (Tuesday, October 11, 2016, 19:15 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 September 1, 2016 (0000h PST) through September 30, 2016 (2359h PDT):
Mt Shasta: Two earthquakes at or above M1.0 were detected, with the largest registering M2.58.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: Seven earthquakes at or above M1.0 were detected, with the largest registering M2.07.
Clear Lake Volcanic Field: Two earthquakes at or above M1.0 were detected, with the largest registering M1.69. [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 M2.95].
Long Valley Volcanic Region: In Long Valley Caldera, 35 earthquakes of M1.0 or greater were detected, with the largest event registering M3.29. One earthquake at or above M1.0 was detected in the Mono Craters region (M1.53). No earthquakes at or above M1.0 were detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M3.07].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Thirteen earthquakes of M1.0 or greater were detected, with the largest registering M1.71. Additionally, a seismic swarm began on September 26 in the Brawley Seismic Zone near the southern terminus of the San Andreas Fault and about 12 km north of Salton Buttes. The largest earthquake registered M4.3. The swarm does not appear to be related to volcanic activity. Two previous swarms occurred in the area in 2009 and 2001.
Coso Volcanic Field: The typical high level of seismicity was observed, with 14 earthquakes M1.0 or greater. The largest registered M2.44.


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Thursday, September 1, 2016, 10:06 AM PDT (Thursday, September 1, 2016, 17:06 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 August 1, 2016 (0000h PST) through August 31, 2016 (2359h PDT):
Mt Shasta: No earthquakes at or above M1.0 were detected.
Medicine Lake: Two earthquakes at or above M1.0 were detected, with the largest registering M1.71.
Lassen Volcanic Center: One earthquake at or above M1.0 was detected (M1.70).
Clear Lake Volcanic Field: One earthquake at or above M1.0 was detected (M1.47). [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 M2.96].
Long Valley Volcanic Region: In Long Valley Caldera, 56 earthquakes of M1.0 or greater were detected, with the largest event registering M3.53. Many of these events occurred during minor earthquake swarms on August 10-15, 2016 and August 21, 2016 about 4 and 8 km, respectively, southeast of the town of Mammoth Lakes. Three earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M1.37. One earthquake at or above M1.0 (M1.09) was detected under Mammoth Mountain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event registered M3.49].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Eleven earthquakes of M1.0 or greater were detected. The largest registered M1.83.
Coso Volcanic Field: The typical high level of seismicity was observed, with 5 earthquakes M1.0 or greater. The largest registered M2.78.


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/.