【摘要】 理论及实验研究显示,震源区的位置和最大震级不仅可能与构造和历史有关,更重要的是与应力状态包括其方向、大小、增加速率、集中位置等以及岩体自身性质,包括其强度、杨氏模量、应变大小及增长速率、裂缝(断层)大小和数量等有关,同时与作用方式有关.综合考虑各种因素,探讨了利用应变能积累确定强震位置和震级的方法:首先对利用形变空间特征变化判断强震震源区位置的方法进行了讨论;接着着重提出估算应变能的初步方法:一是由地表裂缝最大错距和裂缝(断层)长度比估算地震释放能量;二是由新构造运动分区块体体积、年平均应变速率及杨氏模量估算块体应变能积累;进而依据能量估算地震震级;最后以实例论述了应变能积累过程及特点对地震安全性评价的重要作用.更多还原

【Abstract】 Theoretical and experimental studies show that the largest earthquake magnitude and source location in a potential source region are related not only to the structure and history,but also more significantly to the stress state,including direction,level,increasing rate and concentration location,and to the property of a rock body,including strength,Young’s modulus,strain degree,growth rate,size and number of fissures (faults),as well as to the action pattern. By comprehensive consideration of all these factors,this paper focuses on discussing the methods used to determine the magnitude and location of a strong earthquake based on strain energy accumulation. Firstly,we elaborate on a method which can be used to determine a source region by variation in spatial characteristics of deformation. Then a preliminary method for estimating strain energy is presented. Specifically,energy release of an earthquake is estimated by the ratio of maximum dislocation to the length of surface fissure (fault),and strain energy accumulation is estimated based on the block volume of neotectonic movement,annual mean strain rate and Young’s modulus. Thus,earthquake magnitude in a potential source region is determined on the basis of energy. Examples are used to discuss the important role of strain energy accumulation process and its characteristics in seismic safety evaluation.更多还原