3D Inversion for Kinematic Earthquake Source Parameters

University Of California-Santa Barbara, Santa Barbara CA

Investigators

Abstract

EAR-0073899 Archuleta, Ralph The major focus of this proposal is to determine the kinematics of the earthquake rupture process on a finite fault by investing seismic waveforms that include 3D earth structure. The rupture process on the fault is deduced by iteratively fitting the synthetic ground motions to the data. The Green's functions play a critical role in the calculation. Finite difference methods can be used to calculate the Green's functions for a complex, 3D earth structure. Including these 3D Green's functions in inversions for the kinematic source parameters on a finite fault is a natural extension of current methods for determining the parameters of earthquake rupture. To further improve the inversions special functions (cubic B-spline) can be used to discretize the spatial distribution of the kinematic parameters on a finite fault. The 3D Green's functions and the cubic B-spline functions will be combined with a newly developed nonlinear inversion method that is necessary for a global search of the kinematic parameters needed to describe the rupture. Data from the California earthquakes, 1979 M 5.9 Coyote Lake, 1989 M 7.1 Loma Prieta, 1994 M 6.7 Northridge, and the 1999 M 7.7 Chi Chi, Taiwan earthquake will be analyzed.