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CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Monday, December 2, 2019, 10:46 AM PST (Monday, December 2, 2019, 18:46 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 November 1, 2019 (0000h PST) through November 30, 2019 (2359h PST):
Mount Shasta: Two earthquakes at or above M1.0 were detected, the largest of which was M1.06.
Medicine Lake: One earthquake at or above M1.0 was detected (M2.80).
Lassen Volcanic Center: No earthquakes at or above M1.0 were detected.
Clear Lake Volcanic Field: Three earthquakes at or above M1.0 were detected, the largest of which was M2.45. [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 M4.15].
Long Valley Volcanic Region: In Long Valley Caldera, 92 earthquakes of M1.0 or greater were detected, with the largest registering M2.93. One earthquake at or above M1.0 was detected in the Mono Craters region (M1.57). Six earthquakes at or above M1.0 were detected under Mammoth Mountain (the largest of which measured M2.17). [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range, with the largest registering M2.91.]
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Twenty-six earthquakes at or above M1.0 were detected, the largest of which was M2.56.
Coso Volcanic Field: Two hundred eleven earthquakes at or above M1.0 were detected. The largest registered M3.05.


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, November 7, 2019, 9:57 AM PST (Thursday, November 7, 2019, 17:57 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, 2019 (0000h PST) through October 31, 2019 (2359h PST):
Mount Shasta: No earthquakes at or above M1.0 were detected.
Medicine Lake: One earthquake at or above M1.0 was detected (M2.00).
Lassen Volcanic Center: Two earthquakes at or above M1.0 were detected, the largest of which was M1.36.
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 M3.12].
Long Valley Volcanic Region: In Long Valley Caldera, 102 earthquakes of M1.0 or greater were detected, with the largest registering M2.57. Two earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest at M1.70. Seven earthquakes at or above M1.0 were detected under Mammoth Mountain (the largest of which measured M1.82). [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range, with the largest registering M2.83.]
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: No earthquakes at or above M1.0 were detected.
Coso Volcanic Field: No earthquakes at or above M1.0 were detected.


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, October 2, 2019, 10:45 AM PDT (Wednesday, October 2, 2019, 17:45 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, 2019 (0000h PST) through September 30, 2019 (2359h PST):
Mt Shasta: Thirty-eight earthquakes at or above M1.0 were detected, the largest of which was M2.72. These events were part of a minor earthquake series that occurred September 1-3, ~5 km southeast of the summit of Mount Shasta.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: Three earthquakes at or above M1.0 were detected, the largest of which was M1.41.
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 M2.92].
Long Valley Volcanic Region: In Long Valley Caldera, 350 earthquakes of M1.0 or greater were detected, with the largest registering M2.97. Many of these earthquakes were associated with a minor seismic swarm that occurred on September 12-15, on the eastern outskirts of Mammoth Lakes. No earthquakes at or above M1.0 were detected in the Mono Craters region. One earthquake at or above M1.0 was detected under Mammoth Mountain (M1.91). [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range, with the largest registering M2.99.]
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Ten earthquakes were detected registering M1.0 or greater. The largest was M2.34.
Coso Volcanic Field: 450 earthquakes of M1.0 or greater were detected, with the largest registering M3.69.


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
Tuesday, September 3, 2019, 10:45 AM PDT (Tuesday, September 3, 2019, 17:45 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, 2019 (0000h PST) through August 31, 2019 (2359h PST):
Mt Shasta: Three earthquakes at or above M1.0 were detected, the largest of which was M1.79.
Medicine Lake: One earthquake at or above M1.0 was detected (M1.20).
Lassen Volcanic Center: Two earthquakes at or above M1.0 were detected, the largest of which was M1.40.
Clear Lake Volcanic Field: Two earthquakes were detected registering M1.0 or greater. The largest event was M1.04. [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 M2.75].
Long Valley Volcanic Region: In Long Valley Caldera, 100 earthquakes of M1.0 or greater were detected, with the largest registering M2.92. Many of these earthquakes were associated with several minor seismic swarms that occurred on August 23-24, ~2-7 km east of Mammoth Lakes. Two earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M1.58. 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, with the largest registering M2.67.]
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Nine earthquakes were detected registering M1.0 or greater. The largest was M1.84.
Coso Volcanic Field: 1116 earthquakes of M1.0 or greater were detected, with the largest registering M5.01. Many of these events were associated with a seismic swarm that occurred on August 22-23 at the southern margin of Coso Volcanic Field. Recent elevated seismicity in the region is described in CalVO Information Statements and at https://volcanoes.usgs.gov/observatories/calvo/.


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 12, 2019, 11:20 AM PDT (Monday, August 12, 2019, 18:20 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, 2019 (0000h PST) through July 31, 2019 (2359h PST):
Mt Shasta: One earthquake at or above M1.0 was detected (M1.63).
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: Six earthquakes at or above M1.0 were detected, the largest of which was M2.02.
Clear Lake Volcanic Field: Four earthquakes were detected registering M1.0 or greater. The largest event was M1.59. [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 M3.19].
Long Valley Volcanic Region: In Long Valley Caldera, 33 earthquakes of M1.0 or greater were detected, with the largest registering M1.77. Three earthquakes at or above M1.0 were detected in the Mono Craters region, with the largest registering M1.84. Four earthquakes at or above M1.0 were detected under Mammoth Mountain. The largest event was M1.52. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range, with the largest registering M3.30.]
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Nine earthquakes were detected registering M1.0 or greater. The largest was M1.73.
Coso Volcanic Field: In the month of July, 4721 earthquakes of M1.0 or greater were detected, with the largest registering M5.50. Most of these events were associated with a seismic swarm that occurred from July 5 to 26 at the southern margin of Coso Volcanic Field. This swarm is described in recent CalVO Information Statements and at https://volcanoes.usgs.gov/observatories/calvo/.


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


COSO VOLCANIC FIELD VOLCANO (VNUM #323180)
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:
https://volcanoes.usgs.gov/volcanoes/coso_volcanic_field/
https://www.usgs.gov/news/update-magnitude-71-earthquake-southern-california


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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Wednesday, July 10, 2019, 3:01 PM PDT (Wednesday, July 10, 2019, 22:01 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, 2019 (0000h PST) through June 30, 2019 (2359h PST):
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 (M1.50).
Clear Lake Volcanic Field: Two earthquakes were detected registering M1.0 or greater. The largest event was M1.19. [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 M4.07].
Long Valley Volcanic Region: In Long Valley Caldera, 43 earthquakes of M1.0 or greater were detected, with the largest registering M2.71. No earthquakes at or above M1.0 were detected in the Mono Craters region. Four earthquakes at or above M1.0 were detected under Mammoth Mountain, with the largest registering M1.74. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range, with the largest registering M2.75.]
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Fourteen earthquakes were detected registering M1.0 or greater. The largest was M2.98.
Coso Volcanic Field: Fourteen earthquakes of M1.0 or greater were detected in the month of June, with the largest registering M2.17. Note that the ongoing earthquake swarm at the southern margin of Coso Volcanic Field is described in recent CalVO Information Statements and at https://volcanoes.usgs.gov/observatories/calvo/.


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 INFORMATION STATEMENT
U.S. Geological Survey
Wednesday, July 10, 2019, 10:28 AM PDT (Wednesday, July 10, 2019, 17:28 UTC)


COSO VOLCANIC FIELD VOLCANO (VNUM #323180)
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 seismic activity that started on the evening of July 5 at the southern margin of Coso Volcanic Field in Inyo County, California continues at a rate of about 600 M1.0 or greater earthquakes per day. The activity was triggered by a magnitude M5.4 earthquake at 9:19 PM PDT located 20 km (~20 miles) ESE of Little Lake, which itself was an aftershock of the M7.1 earthquake that occurred about an hour earlier on the 5th, located 17 km NNE of Ridgecrest to the south. The intensity of the activity at Coso is gradually declining. Of the approximately 1600 earthquakes detected at M1.0 or above since July 8, only 12 have been M3.0 or above, with the largest two registering M4.1.

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. No ground deformation indicative of volcanic activity has been detected, and there is no imminent threat of an eruption. 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:
https://volcanoes.usgs.gov/volcanoes/coso_volcanic_field/
https://earthquake.usgs.gov/earthquakes/map/

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/.


CALIFORNIA VOLCANO OBSERVATORY INFORMATION STATEMENT
U.S. Geological Survey
Saturday, July 6, 2019, 10:42 AM PDT (Saturday, July 6, 2019, 17:42 UTC)


COSO VOLCANIC FIELD VOLCANO (VNUM #323180)
36°1'48" N 117°49'12" W, Summit Elevation 7874 ft (2400 m)
Current Volcano Alert Level: NORMAL
Current Aviation Color Code: GREEN

An earthquake swarm started on the evening of July 5 at the southern margin of Coso Volcanic Field in Inyo County, California. The swarm activity was triggered by a magnitude M5.4 earthquake at 9:19 PM PDT located 20 km (~20 miles) ESE of Little Lake, which itself was likely an aftershock of the M7.1 earthquake that occurred about an hour earlier 17 km NNE of Ridgecrest, and south of the Coso area. An average of about 30 earthquakes per hour have been detected since, most within the range of magnitude M1 to M3. No ground deformation indicative of volcanic activity has been detected, and there is no imminent threat of an eruption. 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:
https://volcanoes.usgs.gov/volcanoes/coso_volcanic_field/
https://earthquake.usgs.gov/earthquakes/map/

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/.


CALIFORNIA VOLCANO OBSERVATORY MONTHLY UPDATE
U.S. Geological Survey
Thursday, June 6, 2019, 9:33 AM PDT (Thursday, June 6, 2019, 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 May 1, 2019 (0000h PST) through May 31, 2019 (2359h PST):
Mt Shasta: Five earthquakes at or above M1.0 were detected, with the largest registering M1.58.
Medicine Lake: No earthquakes at or above M1.0 were detected.
Lassen Volcanic Center: One earthquake at or above M1.0 was detected (M1.41).
Clear Lake Volcanic Field: One earthquake was detected registering M1.0 or greater (M2.11). [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 M3.03].
Long Valley Volcanic Region: In Long Valley Caldera, 24 earthquakes of M1.0 or greater were detected, with the largest registering M1.56. No earthquakes at or above M1.0 were detected in the Mono Craters region. One earthquake at or above M1.0 was detected under Mammoth Mountain, registering M1.37. [Note: The typical high level of seismicity was observed south of the caldera in the Sierra Nevada range, with the largest registering M2.96.]
Ubehebe Craters: No earthquakes at or above M1.0 were detected.
Salton Buttes: Twelve earthquakes were detected registering M1.0 or greater. The largest was M1.48.
Coso Volcanic Field: Sixteen earthquakes of M1.0 or greater were detected, with the largest registering M2.54.


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/.