临震前地壳变形不动点现象与机制研究  

On the Fixed Points in Crust Deformation prior to Wenchuan Earthquake and Dynamic Background

作　　者：牛安福[1] 张凌空[1] 章静[1] 李媛[2] 赵静[1] 闫伟[1] 岳冲[1] 苑争一 NIU Anfu;ZHANG Lingkong;ZHANG Jing;LI Yuan;ZHAO Jing;YAN Wei;YUE Chong;YUAN Zhengyi(China Earthquake Networks Center,5 Nanheng Street,Sanlihe,Beijing 100045,China;The First Monitoring and Application Center,CEA,7 Naihuo Road,Tianjin 300180,China)

机构地区：[1]中国地震台网中心,北京市100045 [2]中国地震局第一监测中心,天津市300180

出　　处：《大地测量与地球动力学》2020年第1期1-6,共6页Journal of Geodesy and Geodynamics

基　　金：国家重点研发计划(2018YFC1503606);国家自然科学基金(41330314)~~

摘　　要：在综合分析国内外地形变前兆研究现状的基础上,结合汶川8.0级地震前GPS、应变、重力等研究结果,提出临震前震源区域可能出现变形不动点现象。地壳变形过程中的不动点现象是临震前区域应力场进入临界状态的重要标志,是地震潜在危险区域划定的重要依据。借助不动点理论,给出汶川地震前变形不动点集合的演化,结合大区域地震活动空区与远场显著形变异常分布,探讨变形不动点现象发生的动力学背景,验证了汶川地震前地壳变形的不动点现象是大区域应力场有序运动的结果。Based on comprehensive analysis of the research of deformation precursors at home and abroad,this paper,based on the results of GPS,strain and gravity before the Wenchuan earthquake,and applying the tilt data observed around the Wenchuan earthquake,puts forward the phenomenon of‘fixed point’,that may occur in the focal area before the earthquake.The fixed point phenomenon in crustal deformation is an important marker of the critical state of regional stress field before earthquakes,and is an important basis for the delineation of seismic risk area.With the help of the fixed point theory,the evolution of the set of deformation fixed points before Wenchuan earthquake is shown,and the deformation fixed point phenomenon before earthquakes is also explained by thin plate theory.Finally,combined with the distribution of seismic activity and the far field significant deformation anomaly,we discuss the dynamic background of the deformation fixed point phenomenon,and verify that the fixed point phenomenon of the crustal deformation before the Wenchuan earthquake is the result of the orderly movement of the stress field in the large area.

关 键 词：汶川地震 地形变观测 变形不动点 动力背景 

分 类 号：P228[天文地球—大地测量学与测量工程] P313[天文地球—测绘科学与技术]