Source parameters and tectonic setting of the 1990 Lee Vining, California, earthquake sequence

Abstract

AbstractOn 24 October 1990, a magnitude 5.0 (Md) earthquake occurred near Lee Vining, California. It was a strike-slip event with a hypocenter 5 km east and 11.5 km below the surface trace of the Sierran frontal fault, which at this locality has 21 m of Holocene vertical offset. A time-domain deconvolution technique was used to estimate the source-time function of this event using a small foreshock as an empirical Green's function. The resulting source-time function indicates a simple rupture process. The moment for this event is 3.0 × 1023 dyne-cm, and the static stress drop is 36 bars.Moderate-sized earthquakes occurring in the western Basin and Range since 1978 have been concentrated in the central part of the Walker Lane Belt. This is an area of diverse topography and numerous strike-slip faults that lies between the Sierra Nevada Mountains on the west and typical Basin and Range topography on the east. Most of these earthquakes have strike-slip focal mechanisms, and with the exception of earthquakes in the Long Valley Caldera area, they are consistent with left-lateral slip on faults that trend northeast and right-lateral slip on faults that trend northwest.