Spatial correlation of selected earthquakes with the Dog Valley Fault in northern California using LiDAR and GPS data.
The 1966 M6.0 Truckee earthquake has a reported location of 39.438°N 120.160°W at ~10 km depth (Ryall et al., 1968), ~5 km southwest of the Stampede Dam, an earth-fill structure built in 1970 to impound 226,500 acre-feet of water (DWR, 2017). USBR estimates 148,400 people living downstream along the Truckee River would be affected should the Stampede Dam fail. The Truckee earthquake was attributed to the previously unrecognized Dog Valley Fault (DVF) whose surface trace has remained elusive. The Seismo-Lineament Analysis Method, focal mechanisms and location data for earthquakes and aftershocks originating nearby since 1966, geomorphic analysis based on newly acquired LiDAR data, and geological fieldwork were used to search for the DVF. We found small 10 cm wide vertical faults with horizontal shear striae on the drought-exposed shoreface of the reservoir within ~50 m of the upstream side of the dam, on both the north and south sides.