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CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
Friday, April 11, 2014 12:32 PM PDT (Friday, April 11, 2014 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 Caldera and Mono-Inyo Chain, Coso Volcanic Field, Ubehebe Craters, and Salton Buttes.





Observations for March 1, 2014 (0000h PST) through March 31, 2014 (2359h PDST):

Mt Shasta:: Three earthquakes of M1.0 or greater were detected; the largest was a M2.0.

Medicine Lake: No earthquakes of M1.0 or greater were detected.

Lassen Volcanic Center: Six earthquakes of M1.0 or greater were detected (M 1.4 maximum).

Clear Lake Volcanic Field: Six M1.0 or greater earthquakes were detected. The largest earthquake was a M1.9. [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was a M2.8].

Long Valley Caldera and Mono-Inyo Chain: The earthquake swarm that occurred beneath Mammoth Mountain in February subsided, with only one M1.1 earthquake in March (although several M<1.0 earthquakes were detected, as usual). Elsewhere in the region, thirty-eight earthquakes of M1.0 or greater were located in the Long Valley Caldera (maximum M2.7). Two earthquakes of M1.0 or greater were detected under the Mono-Inyo chain (M1.6 maximum). [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event was M2.7]

Ubehebe Craters: No earthquakes at or above M1.0 were detected.

Salton Buttes: The typical high level of seismicity was observed in the vicinity of the buttes, with twenty-nine earthquakes above M1.0 and greater (M3.4 maximum).

Coso Volcanic Field: The typical high level of seismicity was observed, with thirty-eight earthquakes above M1.0 and greater (M3.1 maximum).

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
Tuesday, March 11, 2014 4:34 PM PDT (Tuesday, March 11, 2014 23:34 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. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for February 1, 2014 (0000h PST) through February 28, 2014 (2359h PST):
Mt Shasta:: No earthquakes of M1.0 or greater were detected.
Medicine Lake: One earthquake of M1.0 or greater (M 1.8) was detected.
Lassen Volcanic Center: Three earthquakes of M1.0 or greater (largest M 1.5) were detected.
Clear Lake Volcanic Field: Three M1.0 or greater earthquakes were detected. The largest earthquake was a M1.2. [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was a M2.9].
Long Valley Caldera and Mono-Inyo Chain: An earthquake swarm occurred beneath Mammoth Mountain, lasting from about February 3-18. Though Mammoth Mountain is the site of frequent earthquake swarms, this was one of the largest since a protracted swarm in 1989. The February swarm included 166 earthquakes of M1.0 or larger, most at depths of ~5 km below the surface. The largest event was M 3.1 on Feb 5, which was felt by some residents of the town of Mammoth Lakes. The swarm is likely related to migration of deep-seated hydrothermal fluids. No accompanying changes in surface deformation or gas emissions have yet been detected. Elsewhere in the region, forty earthquakes of M1.0 or greater were located in the Long Valley Caldera, with a maximum M2.6. No earthquakes M1.0 or greater were detected under the Mono-Inyo chain. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event was M2.5]

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
Tuesday, February 11, 2014 4:34 PM PST (Wednesday, February 12, 2014 00:34 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. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for January 1, 2014 (0000h PST) through January 31, 2014 (2359h PST):
Mt Shasta:: No earthquakes of M1.0 or greater were detected.
Medicine Lake: No earthquakes of M1.0 or greater were detected.
Lassen Volcanic Center: One M1.0 earthquake was detected.
Clear Lake Volcanic Field: Eight M1.0 or greater earthquakes were detected. The largest earthquake was a M1.9. [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was a M4.5].
Long Valley Caldera and Mono-Inyo Chain: Fifteen earthquakes of M1.0 or greater were located in the Long Valley Caldera, with a maximum M2.3. Four earthquakes M1.0 or greater were detected under the Mono-Inyo chain, with the maximum M1.6. Nine M1.0 or greater earthquakes were detected under Mammoth Mountain. The maximum was M2.0. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event was M2.6]

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
Friday, January 10, 2014 1:22 PM PST (Friday, January 10, 2014 21:22 UTC)


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


Activity Update: All volcanoes monitored by CalVO's telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for December 1, 2013 (0000h PST) through December 31, 2013 (2359h PST):
Mt Shasta:: Two earthquakes of M1.0 or greater were detected. The maximum was M1.4.
Medicine Lake: One M1.3 earthquake was detected.
Lassen Volcanic Center: Four M1.0 or greater earthquakes were detected, M1.3 was the maximum.
Clear Lake Volcanic Field: Four M1.0 or greater earthquakes were detected. The largest earthquake was a M2.0. [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was a M3.4].
Long Valley Caldera and Mono-Inyo Chain: Twenty-three earthquakes of M1.0 or greater were located in the Long Valley Caldera, with a maximum M2.7. One M1.7 was located under the Mono-Inyo chain, with the maximum M1.7. Six M1.0 or greater earthquakes were detected under Mammoth Mountain. The maximum was M2.3. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event was M2.6]

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
Saturday, December 7, 2013 11:36 AM PST (Saturday, December 7, 2013 19:36 UTC)


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


Activity Update: All volcanoes monitored by CalVO's telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for November 1, 2013 (0000h PST) through November 30, 2013 (2359h PDT):
Mt Shasta: No M1 or greater earthquakes were detected.
Medicine Lake: One M1.6 earthquake was detected.
Lassen Volcanic Center: Five earthquakes of M1 or greater were detected, Maximum M2.31.
Clear Lake Volcanic Field: Three earthquakes M1 or greater were detected. The largest earthquake was M1.9. [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M=3.43].
Long Valley Caldera and Mono-Inyo Chain: Three earthquakes of M1 or greater were located in the Long Valley Caldera, with a maximum of M1.4. Three M1 or greater earthquakes were located on the Mono-Inyo chain, with the maximum M1.7. Two M1 or greater earthquakes were detected under Mammoth Mountain. The maximum was M1.9. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event was M2.82]

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
Thursday, November 7, 2013 9:40 AM PST (Thursday, November 7, 2013 17:40 UTC)


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


Activity Update: All volcanoes monitored by CalVO's telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for October 1, 2013 (0000h PDT) through October 31, 2013 (2359h PDT):
Mt Shasta: 7 earthquakes were detected, the largest was a M 1.2.
Medicine Lake: No earthquakes M 1.0 or greater were detected.
Lassen Volcanic Center: 6 earthquakes were detected, the largest was M 1.3.
Clear Lake Volcanic Field: 17 earthquakes were detected, the largest was a M 1.4. [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M3.1].
Long Valley Caldera and Mono-Inyo Chain: 71 earthquakes were detected in Long Valley Caldera, the largest of which was M 1.9. Three earthquakes were detected along the Mono-Inyo chain (maximum M 1.7). No earthquakes M 1.0 or greater 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 was M 3.8, which was felt by some residents of Mammoth Lakes and Bishop].

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
Tuesday, October 1, 2013 12:21 PM PDT (Tuesday, October 1, 2013 19:21 UTC)


The U.S. Volcano Observatories will remain operational during the lapse of federal government appropriations. Basic volcano monitoring will continue, as will forecasts and regular updates of volcanic activity. However, because of reduced staff, instrument network maintenance will cease, meaning that our monitoring capability will degrade over time. Our websites will remain functional, but only those pages containing information about current volcano hazards will be maintained.

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


Activity Update: All volcanoes monitored by CalVO's telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for September 1, 2013 (0000h PDT) through September 30, 2013 (2359h PDT):
Mt Shasta: Two earthquakes were detected, the largest was a M1.5.
Medicine Lake:No earthquakes M1.0 or greater were detected.
Lassen Volcanic Center: Only one M1.9 earthquake was detected.
Clear Lake Volcanic Field: Two earthquakes were detected, the largest was a M1.4. [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M2.7].
Long Valley Caldera and Mono-Inyo Chain: Thirty-two earthquakes were detected in Long Valley Caldera, the largest of which was a M2.2. Four earthquakes were detected along the Mono-Inyo chain (maximum M1.7). No earthquakes M1.0 or greater 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 was M2.2].

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
Friday, September 6, 2013 12:04 PM PDT (Friday, September 6, 2013 19:04 UTC)


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


Activity Update: All volcanoes monitored by CalVO's telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for August 1, 2013 (0000h PDT) through August 31, 2013 (2359h PDT):
Mt Shasta: One M1.5 earthquake was detected.
Medicine Lake:No earthquakes M=1 or greater were detected.
Lassen Volcanic Center: Ten earthquakes M=1 or greater were detected (maximum was M1.8).
Clear Lake Volcanic Field: Seven earthquakes were detected of magnitude M=1.0 or greater (largest event was M1.4). [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M=3.7].
Long Valley Caldera and Mono-Inyo Chain: Twenty-six earthquakes of M1.0 or greater were located in the Long Valley Caldera, with a maximum magnitude of M3.0. These events are the tail end of a swarm that started in the late afternoon of 17 June 2013 just east of the town of Mammoth Lakes, California (in an area known to geologists as the south moat). Four earthquakes were detected along the Mono-Inyo chain (maximum M1.8) and two earthquakes were detected under Mammoth Mountain (maximum 1.1). [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event was M2.0]

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
Friday, September 6, 2013 11:56 AM PDT (Friday, September 6, 2013 18:56 UTC)


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


Activity Update: All volcanoes monitored by CalVO's telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for August 1, 2013 (0000h PDT) through August 31, 2013 (2359h PDT):
Mt Shasta: One M1.5 earthquake was detected.
Medicine Lake:No earthquakes M=1 or greater were detected.
Lassen Volcanic Center: Ten earthquakes M=1 or greater were detected (maximum was M1.8).
Clear Lake Volcanic Field: Seven earthquakes were detected of magnitude M=1.0 or greater (largest event was M1.4). [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M=3.7].
Long Valley Caldera and Mono-Inyo Chain: Twenty-six earthquakes of M1.0 or greater were located in the Long Valley Caldera, with a maximum magnitude of M3.0. These events are the tail end of a swarm that started in the late afternoon of 17 June 2013 just east of the town of Mammoth Lakes, California (in an area known to geologists as the south moat). Four earthquakes were detected along the Mono-Inyo chain (maximum M1.8) and two earthquakes were detected under Mammoth Mountain (maximum 1.1). [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range. The largest event was M2.0]

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://volcano.wr.usgs.gov/vsc/observatories/calvo.html. 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
Friday, August 23, 2013 1:37 PM PDT (Friday, August 23, 2013 20:37 UTC)


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


Activity Update: All volcanoes monitored by CalVO's telemetered, real-time sensor networks exhibit normal levels of background seismicity and deformation. Real-time monitoring networks are in place at Mount Shasta, Medicine Lake Volcano, Clear Lake Volcanic Field, Lassen Volcanic Center, Long Valley Caldera and Mono-Inyo Chain.


Observations for July 1, 2013 (0000h PDT) through July 31, 2013 (2359h PDT):
Mt Shasta: Two earthquakes were detected, the largest was a M2.9.
Medicine Lake:No earthquakes M=1 or greater were detected.
Lassen Volcanic Center: No earthquakes M=1 or greater were detected.
Clear Lake Volcanic Field: Four earthquakes were detected of magnitude M=1.0 or greater (largest event was M1.7). [Note: Typical high level of seismicity was observed under the Geysers steam field located at the western margin of CLVF. The largest event was M=3.7].
Long Valley Caldera and Mono-Inyo Chain: Thirty-one earthquakes of M1.0 or greater were located in the Long Valley Caldera, with a maximum event registered M2.6. These events are the tail end of a swarm that started in the late afternoon of 17 June 2013 just east of the town of Mammoth Lakes, California (in an area known to geologists as the south moat). One M1.8 earthquake was detected along the Mono-Inyo chain and another M1.2 earthquake 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 was M=2.2]

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://volcano.wr.usgs.gov/vsc/observatories/calvo.html. 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/.