Seismic Moment Tensors and Finite-Source Analysis of Chi-Chi Aftershocks

iii Strong motion data for aftershocks of the September 1999 Chi-Chi, Taiwan earthquake sequence, compiled by PEER Lifelines, were investigated to determine seismic moment tensors, finite-source models, and to evaluate event locations. This data set provided by the Taiwan Central Weather Bureau consisted of strong motion accelerograms from 30 aftershocks with local magnitudes (ML) between 4 to 6.8. Finite-source parameters were obtained for 6 of the large (M6+) aftershocks, seismic moment tensors for 4 of the M5+ aftershocks, and style of fault information for 15 of the aftershocks was determined. Analysis of event locations using both P and S-wave picks and a grid search routine indicates that the locations provided with the waveform data set are adequate for use in determining attenuation relationships