Spatial correlation of earthquakes with two known and two suspected seismogenic faults, north Tahoe-Truckee area, California.
The Seismo-Lineament Analysis Method (SLAM) is used with relocated hypocenters and revised focal mechanisms from 29 M≥3 earthquakes reported in the north Tahoe-Truckee area, California, to spatially correlate earthquakes with the Dog Valley fault zone, the Polaris fault, and two trends that exhibit geomorphic evidence of faulting: the Martis Creek and Prosser Creek trends. These faults and trends are orthogonal-to-conjugate to each other, and are proximate to reservoirs and dam structures whose failure might impact downstream communities along the Truckee River, including Reno. Earthquakes were spatially associated with the two faults and with the Martis Creek and Prosser Creek trends, which are inferred to have developed along seismogenic faults. Horizontal infinitesimal strain analysis of GPS velocity data indicates slow clockwise crustal rotation and NW translation consistent with right-lateral shear in the northern Walker Lane, as well as maximum horizontal extension oriented ENE-WSW consistent with average T-axis orientations from focal mechanisms.