华北北部短临前兆场特征与震源过程的数值模拟  

Characteristics of Short-imminent Earthquake Precursory Field in the Northern Part of North China and Numerical Simulation of Earthquake Source Development

作　　者：张国民[1] 石耀霖[1] 张永仙[1] 

机构地区：[1]国家地震局分析预报中心,中国科学院研究生院

出　　处：《中国地震》1995年第4期327-340,共14页Earthquake Research in China

基　　金：国家重点科技攻关项目

摘　　要：本文对华北２０多次Ｍｓ≥５的震例进行了研究，得到了华北北部地震的７项短临异常特征。同时，把短临地震阶段视为震源介质软化和断层蠕动的物理过程，利用各向异性非线性震源模型和有限元方法计算了震源及其周围地区特征点（假定观测点）上的平均应力、最大剪切力、体应变和孔隙压等物理量随时间的变化，通过对这些理论曲线的分析得到了短临地震前兆具有形态多样复杂、数量随时间指数型增长、异常从外围向震中迁移、异常相对集中于发震构造带上和异常幅度越来越大等时空特征，从物理力学的角度一定程度地揭示了地震短临前兆场特征的成因。Based on the to studies of more than 20 earthquakes with Ms≥5 in North China, seven features of short-imminent earthquake precursorshave been summerized in this paper. At the same time, taking short-imminent earthquake stage as physical process of source media softening and fault creep, we calculated temporal variation of mean stress, maximum shear stress, cubic strain and pore pressure in some certain points (supposed stations) in source area and its adjacent area by using anisotropic and nonlinear source model and finite element method. According to analysis to these theory curves, we draw the conclusion that short-imminent earthquake precursors have set of characteristics such as complex shapes, expotential growth number with time, precursors' migration from outside area to source area, which at some certain points reveals the cause of the characteristics of shortimminent earthquake precursory field given upon.

关 键 词：华北 短临前兆场 震源过程 数值模拟 地震前兆 

分 类 号：P315.7[天文地球—地震学]