由地震释放的地震矩叠加推导平均应力场  

MEAN STRESS FIELD INFERRED FROM THE TOTAL SEISMIC MOMENT RELEASED BY EARTHQUAKES

作　　者：盛书中[1,2] 万永革[1,2] 徐志国[3] 卜玉菲 武晔[1] 李迎秋[1] 

机构地区：[1]防灾科技学院,河北三河065201 [2]中国地震局地球物理研究所,北京100081 [3]中国地震台网中心,北京100045 [4]甘肃省地震局,兰州730000

出　　处：《地震地质》2013年第1期92-100,共9页Seismology and Geology

基　　金：中央高校基本科研业务费专项(创新项目团队资助计划)(ZY20110101);国家自然科学基金(41074072);中国地震局地震行业专项(201208009)共同资助

摘　　要：文中给出了根据地震释放的总地震矩求解平均应力场的方法,并使用加入随机误差的人工合成震源机制解数据和唐山余震区震源机制解数据对其进行检验。由检验结果可知,该方法可以应用于区域平均应力场的求解。使用的震源机制解资料越多,所得结果越稳定,且更接近真实的区域应力场。该方法的优点是:用每个地震的震级作为权重,能够较好地反映出大小地震在应力场反演中的不同贡献;并且在计算过程中不需要知道震源机制解2个节面中哪个节面为地震断层面。In this paper,we present a method which allows to calculate the mean stress field according to the total seismic moment released by earthquakes. The exact method is as follows： First,we calculate the scalar seismic moment released by each earthquake according to the statistical relationship between earthquake magnitude and its seismic moment; Second,we calculate the seismic moment tensor released by each earthquake according to the relationship between focal mechanism solution and seismic moment tensor; Then,we can get the total seismic moment tensor released in a specific time period of the study area; Finally,we calculate the eigenvector and eigenvalue of the total seismic moment tensor,the ob- tained eigenvector is corresponding to the mean stress field direction released by the study area. We tested the method by using the synthetic focal mechanism to which random error was added and with the focal mechanism data of Tangshan aftershoek zone. The testing results show that, the released stress field of the study area obtained by our method is in consistency with the regional stress field. So our method can be applied to solve regional stress field. The more focal mechanism data used ,the more stable the result would be, and closer to the real regional stress field. One of the advantages of this method is that it uses magnitude as the weight of each earthquake, so the contribution difference of the earthquake size in the stress field inversion can be better reflected. Another advantage is that it does not need to know which nodal plane of the focal mechanism is the real fault plane when we calculate stress field.

关 键 词：震源机制解 应力场 地震矩 震级 

分 类 号：P315.63[天文地球—地震学]