This Temblor map shows the location of the active earthquake swarm relative to the cities of Reno and Carson City, as well as Lake Tahoe.
This part of the Western United States, in between the Sierra Nevada Microplate and the Basin and Range Province, is what is known as Walker Lane. This shear zone, together with the San Andreas Fault, accommodates the majority of plate motion between the Pacific and North American plates. Walker Lane is predominantly made up of discontinuous sets of right-lateral strike-slip faults. In the area around this morning's swarm, there are several mapped faults, including the Polaris Fault and East Truckee Fault Zone.
While these are known right-lateral faults, consistent with the predominant motion in the area, the sense of slip on today's earthquakes is ambiguous. One of the reasons why this is the case is because due to the small magnitudes, the quakes may have occurred on smaller antithetic faults rather than structures associated with the large northwest-southeast-trending right-lateral faults.
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