Characteristics of strong ground motion during the 1999 Chi-Chi earthquake (Taiwan) and large aftershocks: comparison with the previously established models

摘要

In the Taiwan region, the empirical spectral models for estimating ground motion parameters were obtained recently on the basis of recordings of small to moderate (5.0 ≤ M_L ≤ 6.5) earthquakes. A large collection of acceleration records from the recent M_L 7.3 (M_w 7.6) Chi-Chi earthquake (20 September, 1999) makes it possible to test the applicability of the established relationships in the case of larger events. The comparison of ground motion parameters (peak accelerations and response spectra), which were calculated using the stochastic approach based on the modeled Fourier amplitude spectra, and the observed data demonstrates that the models may be successfully used for ground motion prediction for earthquakes of magnitudes up to M_L = 6.8-7.0 and hypocentral depth more than 10 km. To satisfy to the peculiarities of ground motion during shallow (depth less than 10km) and larger (M_L > 7.0) events, the models were revised.