Three-dimensional dense strong motion waveform inversion for the rupture process of the 1999 Chi-Chi, Taiwan, earthquake

摘要

We inverted the high-resolution spatiotemporal slip distribution of the 21 September 1999 Chi-Chi, Taiwan, earthquake utilizing data from densely distributed island-wide strong motion stations for a three-dimensional (3-D) fault geometry, and 3-D Green's functions calculations based upon parallel nonnegative least squares inversion. The 3-D fault geometry, consistent with high-resolution reflection profile, is determined from GPS inversion and aftershocks distribution. This 3-D fault model presents the dip angle gradually becoming shallower from south to north along the fault and near flat at the deeper portion of the fault. The 3-D Green's functions are calculated through numerical wavefield simulation from three-dimensional heterogeneous velocity structure derived from tomography studies.