SOURCE PARAMETERS AND TECTONIC SETTING OF THE 1990 LEE VINING, CALIFORNIA, EARTHQUAKE SEQUENCE

On 24 October 1990, a magnitude 5.0 (M-d) 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 fu nction of this event using a small foreshock as an empirical Green's f unction. The resulting source-time function indicates a simple rupture process, The moment for this event is 3.0 X 10(23) dyne-cm, and the s tatic stress drop is 36 bars, Moderate-sized earthquakes occurring in the western Basin and Range since 1978 have been concentrated in the c entral part of the Walker Lane Belt, This is an area of diverse topogr aphy and numerous strike-slip faults that lies between the Sierra Neva da Mountains on the west and typical Basin and Range topography on the east. Most of these earthquakes have strike-slip focal mechanisms, an d with the exception of earthquakes in the Long Valley Caldera area, t hey are consistent with left-lateral slip on faults that trend northea st and right-lateral slip on faults that trend northwest.