THE 3-D FINITE ELEMENT ANALYSIS ON THE PREGNANT PROCESS OF TANGSHAN EARTHQUAKE AND ITS SIGNIFICANCE TO THE EARTHQUAKE PREDICTION STUDY
ZHU YUE-QING MEI SHI-RONO LIANG BEI-YANG (Centre for Analysis and Prediction, State Seismological Bureau. Beijing)
In this paper we have studied the physical and mechanical features of pregnant process cf Tangshan earthquake. We analysed the physical characteristics of the pregnant body and its environment, and considered that the body is under the actions of an external force system. We suggest a pregnant physical mechanical model for Tangshan earthquake. Subse-quentely we carry out 3-D mechanical analysis on the pregnant process by using finite element method. We have applied the geophysical measurement data or its reversional results to ascertain the boundary conditions and the physical paramenters of the model medium. Considering that the real model is not a homogeneous one, we think that the friction-slip failure mechanism is suited to real shock-failure situation. Basing on the Byerlee's experience rule we suggested the conception of risk degree of frictional fracturing Fs and used it to cognize the earthquake failure dangerous points. We took Fs≥1.0 as the failure criterion. At last, we have done a concrete analysis on the failure characteristics of Tangshan earthquake, and discussed the significance of this study and its results to earthquake prediction.