A GEOLOGY-BASED 3D VELOCITY MODEL OF THE LOS-ANGELES BASIN SEDIMENTS

Seismic hazard studies of the Los Angeles basin area require a realist ic seismic-velocity model. We use geologic information about depth to crystalline basement, depths to sedimentary horizons, uplift of sedime nts, and surface geology in a velocity-depth-age function to construct a three-dimensional velocity model. In earthquake location tests, the model predicts travel times satisfactorily, and in earthquake ground- motion simulations, the model correctly determines the timing and ampl itude of late-arriving waves.