| dc.description.abstract | The September 20, 1999 (UTC) Mw7.6 Chi-Chi earthquake can be viewed as one of the most devastating and significant events in Taiwan. Although with severe impact, this event provided a remarkable set of data, especially the high-quality near-field strong motion acceleration records from the Taiwan Strong Motion Instrumentation Progam (TSMIP). These data provide us a unique opportunity to have comprehensive understanding on the rupture behavior of earthquake. For two decades, since the 1999 Chi-Chi earthquake, the modeling of earthquake kinematics had been well developed. But nowadays, some questions related to earthquake dynamics still remains unknown. In this study, our goal is to investigate the dynamics of rupture and slip time histories of this event with great help on comprehensive understanding of this earthquake. We construct a 3D dynamic rupture model by finite element method. Based on the constraints of the kinematic study by Ji et al. (2003) and the geophysical logging data from the Taiwan Chelunpu-fault Drilling Project (TCDP), we try to estimate the dynamic parameters (e.g., apparent slip-weakening distance, dc^a) and to determine the state of stress (e.g., initial normal stress, σn) on the fault. In order to understand the characteristics of the dynamic parameters, we designed a series of numerical experiments on homogeneous and heterogeneous model which assume that the fault ruptures with spatially uniform or non-uniform frictional behavior. After various models with different set of dynamic parameters, we find that the parameters for our optimal heterogeneous model are dc=0.5~1.7(m), dc^a=1.9~7.0(m) scaled down by α=0.25, S=0.3~7.5,σn-north=10~92(MPa) and σn-south=3.6~32.3(MPa). The optimal model can simulate a rupture similar to the kinematic study and the maximum slip (~13 m) occurs in the northern part of fault. The total seismic moment M0 is ~4.9*10^20(Nm). The results suggest that could be overestimated due to influence of other dynamic process related to heat or pore pressure for large earthquakes, and the different value of in the northern and southern part of fault might be a key to control the slip pattern. | en_US |