Study Of Focal Mechanism Solutions Of Earthquake Sequences And Regional Stress Field

Crustal tectonic stress field is an important question in geodynamic. Its principal task is discussing the spatial distribution shape of crustal stress field and its dynamic evolvement with time, tracing the evolvement course of crustal tectonic movement., knowing nowaday crustal tectonic activity and its generant mechanism, accordingly forecasting the future evolvement rule of crustal tectonic movement.Earthquake occur because of tectonic stress action from the interior of earth, rock suddenly rupture and slip. Studying on stress field of fault help us realize physical process of earthquake occurrence. So far, general and effective method is via focal mechanism to deduce directions of stress principal axes. Focal mechanism parameters are important data to confer tectonic stress in the focal region of earthquakes, it can reflect mechanical properties and kinetic properties of focal fault, and reveal mechanics mechanism of earthquake rock, give us equivalent release stress field of earthquakes.Stress field has a deformation process in the focal region of a strong earthquake sequence. Based on the time course of focal mechanism of an earthquake sequence to describe dynamic image of release adjustment of stress field, and study variable characteristics of moderate-small earthquake focal mechanisms in the earthquake sequence and variable process of stress field with time, conclude common characteristics of stress field before strong aftershock happen. Based on the accumulation of earthquake example knowledge, it can provide new method and physical mechanics gist of strong aftershock.Aftershock in the earthquake sequence is the result of stress field adjustment in hypocenter region, Stress tensor informations of lots of moderate-small aftershocks focal mechanisms can depict stress field status of hypocenter region, understand temporal and spatial variable characteristics of stress field, and realize the accumulation and adjustment process of stress filed. Studying on temporal and spatial variable of hypocenter region stress field of strong earthquakes help us realize mechanics process of earthquake preparation.This study applies stress tensor inversion method by Gephart to study the variable characteristics of stress field of earthquake sequence. It adopts partial periods method. Based on the variable characteristic of earthquake sequence, divide it into different study periods, study the accumulation and adjustment process of earthquake sequence and variable rule of stress field before mainshock and strong aftershock, conclude common characteristics of stress field. In order to understand the time sequence characteristics of tectonic stress field in the region, combining nowaday tectonic...