新西兰M_W 7.8地震同震和震后效应模拟  

Co-seismic and post-seismic effect simulation of the New Zealand M_W 7. 8 earthquake

作　　者：高阳[1] 张永志[1] 尹文浩 焦佳爽 GAO Yang;ZHANG Yong-zhi;YIN Wen-hao;JIAO Jia-shuang(School of Geology Engineering and Geomatics,Chang＇an University,Xi＇an 710054,China;Xi＇an Institute of Surveying and Mapping,Xi＇an 710054,China)

机构地区：[1]长安大学地质工程与测绘学院,西安710054 [2]西安市勘查测绘院,西安710054

出　　处：《地球物理学进展》2018年第4期1345-1350,共6页Progress in Geophysics

基　　金：国家自然科学基金(41374028;41274083);中央高校基本科研业务费专项资金(310826175018)共同资助

摘　　要：根据地球分层模型CRUST1.0和USGS发布的断层模型,考虑自重的影响,本文利用PSGRN/PSCMP模型计算了黏弹性分层介质中新西兰M_W7.8地震同震及震后位移和重力变化,结合GPS同震位移和模拟值,得到研究区域58个点位3个位移分量的均方根.结果表明:同震位移和重力变化在近场比较明显,远离断层的区域基本为零值;同震位移显示,新西兰M_W7.8地震震源机制在南部以逆冲为主,北部以右旋走滑为主;震后50年水平位移、垂直位移和重力的变化趋势与同震变化基本一致,水平位移在断层投影区以内减小,而在远场增加,垂直位移整体上呈现抬升趋势,重力变化幅度下降,反映了震后壳幔物质黏滞性调整;模拟值和GPS观测值在运动趋势和量级上具有较好的一致性,研究区域南北向位移、东西向位移和垂直位移的均方根分别为0.21 m、0.12 m和0.11 m,整体上模拟效果较好.Based on the CRUST1. 0 model and the fault model released by USGS,considering the gravitational effect,the PSGRN/PSCMP program was used to calculate the co-seismic and postseismic displacement and gravity change of the New Zealand M-W7. 8 earthquake,The Root Mean Square（ RMS） of 3 displacement components at 58 points in the study area is obtained by combining the GPS coseismic displacement and the value from PSGRN/PSCMP. The results show that, the change of the coseismic displacement and the gravity change are obvious in the near field,and the areas further away from the fault is basically zero; the coseismic displacements indicate that the focal mechanism of the New Zealand M-W7. 8 earthquake is mainly thrusting in the south and dextral strike-slip in the north; In the 50 years after the earthquake,the horizontal displacement,vertical displacement and gravity change trend are basically consistent with the coseismic changes,horizontal displacement decreases within the fault projection area,while in the far field increases,the vertical displacement shows an upward trend as a whole,and the change range of gravity decreases,which reflects the viscosity adjustment of crust and mantle after the earthquake; The simulated values and GPS observations have good consistency in motion trend and magnitude.The root mean square of N-S displacement,E-W displacement and vertical displacement in the study area are 0. 21 m,0. 12 m and 0. 11 m respectively,and the overall simulation results are good.

关 键 词：新西兰地震 黏弹分层 同震变化 震后变化 

分 类 号：P315[天文地球—地震学]