Abstract
In the dislocation theory, focal parameters such as the fault area, dislocation, source-time function, rupture velocity, rise time, etc. are assumed in advance of calculation. But, in actual situations, these parameters are the results of fractures on the fault plane. To produce this physical condition in the analysis of the focal rupture mechanism, the process of successive rupture must be analyzed as a phenomenon of fracture caused by external forces on the fault plane. The finite element method is a promising tool for this type of analysis. In this report, only the stress drop and yielding stress values of the fault being considered are assumed. Parameters that are assumed to be controlling parameters in the dislocation theory are obtained by results of numerical computations using the proposed method. In our analysis, rupture begins at some point on the fault where mobilized shear stress reaches the yielding stress value, then the rupture is transmitted successively along the fault. The driving force of successive rupture is the released strain energy produced by the tectonic force applied laterally on the far field of the crust. The focal parameters obtained from simulations compare well with the empirical relationships of focal parameters determined from past seismic data. The analysis is two dimensional, with a thrust type fault plane being treated. Emphasis is on the approach rather than on results developed during application.
