Simulation of Ground Motion Characteristics of the 20 September 1999 Chi-Chi Earthquake Using Semi-Empirical Approach

Abstract

The Chi-Chi earthquake (M7.6) was triggered on 20th September 1999 at 17:47:12 UTC in Chi-Chi, Taiwan. This was the largest inland earthquake occurred in Taiwan region. Chelungpu fault was the main cause for this earthquake and the fault was ruptured over 100 km. The ground motions were recorded at more than 600 stations. This study presents simulation of near field ground motions of 1999 Chi-Chi earthquake. For this purpose, 3 stations on foot wall side and 7 stations on hanging wall side are selected to generate ground motions using semi-empirical approach. The ground motion characteristics of the earthquake are calculated at 10 stations. It is found that the distribution of peak ground acceleration (PGA) obtained from semi-empirical approach, similar to real PGA distribution. Higher frequencies of simulated ground motions match with frequencies of real ground motions.