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Long Valley Caldera range-front faults terminate at the caldera bou...

Detailed Description

This is a simplified diagram of regional range front faults as they intersect the Long Valley Caldera. The Hartley Springs Fault and Hilton Creek Fault are range-front faults caused by regional Basin and Range extension (Earth's crust is pulling apart, and the Sierra Nevada mountains are lifting up and moving to the west as the Basin and Range drops down to the east). Fault movement is normal along the main segments of the Hartley Springs fault and Hilton Creek fault, but those faults end at the rim of the Long Valley Caldera; extension continues into the caldera with dike emplacement related to the Inyo Domes ("Inyo Dike"), and is accommodated by a series of "leaky" right-lateral oblique transform faults south of the resurgent dome in the caldera, causing earthquakes to occur in a west-northwest to east-southeast orientation (called the South Moat Seismic Zone, SMSZ), which is what Dave Hill and Emily Montgomery-Brown, USGS Research Geophysicist at CalVO, observed in seismic data from the Long Valley area in a 2015 publication. Their discovery suggests a lower predicted intensity of potential earthquakes in Mammoth Lakes.


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