A large sequence of temblors is striking Southern California at the moment. This sequence so far is tectonic, not volcanic in origin, however it is striking very close to two dormant volcanic fields: The Coso Volcanic Field, and the Lava Mountains Volcanic Field.
The first major temblor, a magnitude 6.4 quake, spawned many aftershocks along the adjascent fault lines on 7/4/2019, and the second, larger shock struck at very shallow depth to the NW, at a magnitude of 7.1. Multiple aftershocks have since occurred, closer to the epicenters of the Coso Volcanic field, with the largest so fat at magnitude 5.5.
What this means for the area is not known. If this is purely a tectonic sequence, not much damage should occur outside of the immediate area. The Coso Volcanic Field has active geothermal power plants, and a few military installations.
The last identified eruptive period in this area was some 33,000 years ago, although suspected Holocene centers are inferred through morphology. It is tough to gauge the age of these volcanoes due to the desert climate, which can make older volcanism look younger than it actually is.
"July 06, 2019 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.
The first major temblor, a magnitude 6.4 quake, spawned many aftershocks along the adjascent fault lines on 7/4/2019, and the second, larger shock struck at very shallow depth to the NW, at a magnitude of 7.1. Multiple aftershocks have since occurred, closer to the epicenters of the Coso Volcanic field, with the largest so fat at magnitude 5.5.
What this means for the area is not known. If this is purely a tectonic sequence, not much damage should occur outside of the immediate area. The Coso Volcanic Field has active geothermal power plants, and a few military installations.
The last identified eruptive period in this area was some 33,000 years ago, although suspected Holocene centers are inferred through morphology. It is tough to gauge the age of these volcanoes due to the desert climate, which can make older volcanism look younger than it actually is.
Google Earth screenshot with USGS quake overlay, and my volcano database.
More, larger quakes are possible. As has been theorized in the past, large quakes at the Southern end of the San Andreas fault line can propagate to the NW, creating a chain of events, although it is far too soon to see if this is the case.
Earthquakes, fault lines, and volcanic systems can and have interacted with each other in the past, however, given the age of the last eruption at the Coso Volcanic Field, an eruption still remains highly unlikely to occur.
Residents in the vicinity should check their preparedness plans, and have an evacuation kit ready, if necessary, in the event of a larger quake.
Scientists in CA have long stated that CA is locked and loaded for 'The Big One" a quake of 8.0-9.0 in magnitude - and have advised that people have a plan in case of this event. California on average has had a large quake of 8.0 or more every 100 years or so, and for this, they are overdue.
It is important to note that USGS requires ample time to study each significant event, review the waveforms, and study factors like depth, whether these are purely fault slips, and whether subsequent events are purely tectonic in nature. No conclusions can be reached until all the data is in. Again, it is unlikely that this sequence would result in an eruption of nearby volcanic systems, but this is not unprecedented.
******UPDATE 7/8/2019*****
USGS CALVO Released the following statement regarding the Coso Volcanic Field:
"July 06, 2019 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.
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."
Many large earthquakes have hit California in it's very long history. While this can and does create a lot of quake activity near the field, the 'crystal mush' in the magma chamber would still need fresh injection of magma into its chamber to trigger an eruption.
While Coso is not a good candidate for eruption, other volcanoes around the world remain 'primed', or close to an eruption, and a large earthquake sequence could indeed initiate an eruptive event. One such volcano is Mt. Fuji in Japan, which, according to Japanese authorities, is pressurized, and a large earthquake along its intersecting fault line could weaken the pressure on the chamber, thus causing an eruption.
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