Thursday, December 29, 2016

Quake Swarm Along Nevada California Border

A cluster of large earthquakes occurred 12/28/2016 along the CA-NV border with three main events followed by hundreds of smaller quakes. This occurred just north of the Aurora Crater volcanic field along a fault that trends from the Aurora Crater area to Lake Tahoe to the NW. The quake sequence, according to geologists, was tectonic in nature and not related to any volcanism. The last volcanic activity in the area occurred ~25,000 years BP (although the volcanic features are well-preserved due to the arid climate).

Three large quakes struck within hours of each other, at depths ranging from 12km to around 6km. Two quakes registered magnitude 5.7, and were reportedly felt as far away as San Jose to the WSW. The third registered at 5.5, with many aftershocks.


Location of quake swarm. Screenshot form Google using USGS overlay and my modified Smithsonian GVP database. 

According to the Smithsonian GVP, the Bodie-Aurora field is described as follows:

"Aurora-Bodie volcanic field in west-central Nevada near the California border NNE of Mono Lake contains well-preserved cinder cones and lava flows of late Pleistocene age. The most prominent feature, Aurora Crater, is a 25,000 years before present cinder cone surrounded by lava flows. Mud Spring volcano is another late Pleistocene vent with a well-preserved lava flow. Older volcanics of the field include Pliocene andesitic lava domes and Pliocene cones such as Beauty Peak and Mount Hicks."

It is highly unlikely that volcanism is in any way related to this swarm, but full analysis of the swarm is not yet completed by CalVO. Aftershocks are likely for some time, and there is of course always a slight risk that these events could be foreshocks to a stronger event. 

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