鲜水河断裂带跨断层变形分析和数值模拟  

Analysis and numerical simulation of cross-over fault deformation along Xianshuihe fracture zone

作　　者：张晁军[1] 石耀霖[1] 马丽[2] 陈棋福[2] 王武星[1] 

机构地区：[1]中国科学院研究生院,北京100049 [2]中国地震局地震预测研究所,北京100036

出　　处：《地震》2008年第3期23-32,共10页Earthquake

基　　金："973"项目(2004CB418405);国家自然科学基金(40774048;40574020);地震基本科研业务项目(02076902-05)资助

摘　　要：鲜水河断裂带积累了20多年的跨断层变形资料,如何解释这种变形是一个重要的问题。该文采用了弹性上地壳覆盖在粘弹性Max well体之上的模型。炉霍1973年MS7.6地震按该粘弹性模型计算的震后形变曲线能够在很大程度上解释实测观测结果,显示与一些断层(如圣安德烈斯断层某些段落)存在缓慢蠕滑而无大地震发生不同,鲜水河断裂带观测到的跨断层变形,有相当一部分可以用大地震后的粘弹性变形来解释。当然,计算得到的震后粘弹性形变幅度同跨断层短基线和短水准的实测形变幅度比较还存在一些差异,不能完全解释,表明了大陆断层活动的复杂性,并值得进一步深入研究。Data of cross-over fault deformation for more than 20 years have been accumulakind of deformation. This paper adopted the viscoelastic model to study this problem, the lower crust is assumed Maxwell rheology covered by an elastic upper crust. The post-seismic deformation of the Ms7.6 Luhuo earthquake in 1973 computed plain the observation data to a great degree, showing that Xiansh from some faults （such as some of segments in San Andres Fault） by this model can exuihe fault is different , which creeps slowly and there is no large earthquake occurred on it. And a significant part of the cross-over deformation observed along Xianshuihe fracture zone can be explained by post-seismic viscoelastic deformation after large earthquakes. However, this kind of model can not explain the entire deformation. Deviation exists between viscoelastic model and the actual observation of cross-over fault short baseline and short water level. It indicates that the activity of continental faults is complicated and it is worth to further studies.

关 键 词：鲜水河断裂带 跨断层形变 粘弹性模型 无震滑动 数值模拟 

分 类 号：P315.3[天文地球—地震学]