摘要
基于临汾盆地及其周缘的GPS和In SAR观测资料,通过计算最大主应变、最小主应变、面应变等水平形变特征量以及罗云山断裂(南段)上盘雷达视线向形变速率,综合研究汶川M 8.0地震前后临汾盆地及边界断裂现今地壳形变特征。结果显示:汶川M 8.0地震的发生引起临汾盆地及周缘形变场的动态调整,罗云山断裂南段至峨嵋台地北缘断裂应变率场由弱张性活动转为较强的压性活动状态,最大面应变率由1.5×10-8/a变为-3.1×10-8/a,SBAS-In SAR结果同时显示,罗云山断裂(南段)上盘于2009年起由下降转为隆起,在形变场动态调整过程中发生河津M 4.8地震,之后该区域应变率场恢复背景状态;汶川M 8.0地震有利于在山西断陷带南段北东东向断裂间形成压性应变积累,对河津地M 4.8地震的发生可能具有促进作用。
Based on the GPS and In SAR observation data in Linfen basin and its periphery, we study the present-day crustal deformation characteristic of Linfen basin and its periphery before and after the Wenchuan M 8.0 earthquake through calculating the maximum principal strain, the minimum principal strain, plane strain and the LOS deformation rate of the southern part of Luoyunshan fault. The results show that： ① The occurrence of Wenchuan M 8.0 earthquake caused the dynamic adjustment of deformation field in Linfen basin and its margin faults, the strain rate field changes from the weak extentional activity to the strong pressure activity from the south section of Luoyunshan fault to Emei platform northern margin fault, the maximum plane strain rate increases from 1.5×10-8/a to-3.1×10-8/a, the SBAS-In SAR result shows that the upper wall of Luoyunshan fault（the southern section） changes from subsiding to rising, there occurred Hejin M 4.8 earthquake in the process of the deformation field dynamic adjustment. After the Hejin earthquake, the strain rate of the area decreases to the background state. ② Wenchuan M 8.0 earthquake is advantageous to the strain accumulation of NEE faults in south of the Shanxi rift zone, which may prompt the preparation and occurrence of the Hejin M 4.8 earthquake.
出处
《地震地磁观测与研究》
2015年第3期9-13,共5页
Seismological and Geomagnetic Observation and Research
基金
山西省科技攻关计划项目(20140313023-1)
