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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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Monday, August 1, 2016, 10:36 AM PDT (Monday, August 1, 2016, 17:36 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 July 1, 2016 (0000h PST) through July 31, 2016 (2359h PDT):
Mt Shasta: Three earthquakes at or above M1.0 were detected, with the largest registering M1.46.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: Nine earthquakes at or above M1.0 were detected, with the largest registering M2.07. Most of these events occurred during two minor seismic swarms on July 11 and 30, 2016, near the Shasta-Tehama-Plumas County lines, about 7 miles north and 5 miles northeast, respectively, of the town of Mill Creek.
Clear Lake Volcanic Field: Three earthquakes at or above M1.0 were detected, with the largest registering M2.22. [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 M2.83].
Long Valley Volcanic Region: In Long Valley Caldera, 8 earthquakes of M1.0 or greater were detected. The largest event registered M1.94. One earthquake at or above M1.0 was detected in the Mono Craters region (M1.17). 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 M3.09].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Thirty-one earthquakes of M1.0 or greater were detected. The largest registered M2.54.
Coso Volcanic Field: The typical high level of seismicity was observed, with 7 earthquakes M1.0 or greater. The largest registered M1.69.


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
Friday, July 1, 2016, 12:32 PM PDT (Friday, July 1, 2016, 19:32 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 June 1, 2016 (0000h PST) through June 30, 2016 (2359h PDT):
Mt Shasta: One earthquake at or above M1.0 was detected (M1.55).
Medicine Lake: One earthquake at or above M1.0 was detected (M1.11).
Lassen Volcanic Center: One earthquake at or above M1.0 was detected (M1.14).
Clear Lake Volcanic Field: Two earthquakes at or above M1.0 were detected, with the largest registering M1.83. [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 M3.34].
Long Valley Volcanic Region: In Long Valley Caldera, 18 earthquakes of M1.0 or greater were detected. The largest event registered M2.20. 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 M2.44].
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 M1.76.
Coso Volcanic Field: The typical high level of seismicity was observed, with 10 earthquakes M1.0 or greater. The largest registered M2.30.


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
Friday, June 3, 2016, 11:48 AM PDT (Friday, June 3, 2016, 18:48 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, 2016 (0000h PST) through May 31, 2016 (2359h PDT):
Mt Shasta: One earthquake at or above M1.0 was detected (M1.37).
Medicine Lake: Three earthquakes at or above M1.0 were detected; the largest registered M1.57.
Lassen Volcanic Center: One earthquake at or above M1.0 was detected (M1.17).
Clear Lake Volcanic Field: Four earthquakes at or above M1.0 were detected, with the largest registering M1.89. [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 M3.83].
Long Valley Volcanic Region: In Long Valley Caldera, 18 earthquakes of M1.0 or greater were detected. The largest event registered M1.92. 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 M2.20].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Twenty-two earthquakes of M1.0 or greater were detected. The largest registered M2.72.
Coso Volcanic Field: The typical high level of seismicity was observed, with 7 earthquakes M1.0 or greater. The largest registered M1.79.


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 2, 2016, 11:24 AM PDT (Monday, May 2, 2016, 18:24 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 April 1, 2016 (0000h PST) through April 30, 2016 (2359h PDT):
Mt Shasta: No earthquakes at or above M1.0 were detected.
Medicine Lake: One earthquake at or above M1.0 was detected (M1.58).
Lassen Volcanic Center: Two M1.0 or greater earthquakes were detected, with the largest registering M1.87.
Clear Lake Volcanic Field: One earthquake at or above M1.0 was detected (M1.50). [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 M2.83].
Long Valley Volcanic Region: In Long Valley Caldera, 24 earthquakes of M1.0 or greater were detected. The largest event registered M2.87. One earthquake at or above M1.0 was detected in the Mono Craters region (M1.74). 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 M2.91].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Four earthquakes of M1.0 or greater were detected. The largest registered M2.22.
Coso Volcanic Field: The typical high level of seismicity was observed, with 13 earthquakes M1.0 or greater. The largest registered M1.82.


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
Friday, April 1, 2016, 10:28 AM PDT (Friday, April 1, 2016, 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, 2016 (0000h PST) through March 31, 2016 (2359h PDT):
Mt Shasta: One earthquake at or above M1.0 was detected (M1.06).
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: Five M1.0 or greater earthquakes were detected, with the largest registering M1.42. Many of these events occurred during two minor seismic swarms on March 23, 2016 near the Shasta-Tehama-Plumas County lines about 14 km north of the town of Mill Creek and March 26, 2016 near the Shasta-Tehama-Plumas County lines about 8 km north of the town of Mineral.
Clear Lake Volcanic Field: Two M1.0 or greater earthquakes were detected, with the largest registering M2.63. [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, 16 earthquakes of M1.0 or greater were detected. The largest event registered M2.15. 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 M2.58].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Sixteen earthquakes of M1.0 or greater were detected. The largest registered M2.14.
Coso Volcanic Field: The typical high level of seismicity was observed, with 24 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, March 1, 2016, 10:27 AM PST (Tuesday, March 1, 2016, 18:27 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 February 1, 2016 (0000h PST) through February 29, 2016 (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: Twelve M1.0 or greater earthquakes were detected, with the largest registering M2.20. Many of these events occurred during two minor seismic swarms on February 15 and 18, 2016 near the Shasta-Tehama-Plumas County lines about 14 km north of the town of Mill Creek.
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 M2.87].
Long Valley Volcanic Region: In Long Valley Caldera, 25 earthquakes of M1.0 or greater were detected. The largest event registered M2.45. 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 M3.74].
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Seven earthquakes of M1.0 or greater were detected. The largest registered M1.91.
Coso Volcanic Field: The typical high level of seismicity was observed, with 11 earthquakes M1.0 or greater. The largest registered M2.88.


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/.