空间大地测量GPS揭示的汾渭盆地及其邻域现今地壳应变场变化特征  

Current crustal deformation variation characteristics of the Fenwei basin and its surrounding areas revealed by GPS data

作　　者：瞿伟[1,2] 王运生[2] 张勤[1] 王庆良[3] 薛康[1] 

机构地区：[1]长安大学地质工程与测绘学院,西安710054 [2]地质灾害防治与地质环境保护国家重点实验室,成都理工大学,成都610059 [3]中国地震局第二监测中心,西安710054

出　　处：《地球物理学报》2016年第3期828-839,共12页Chinese Journal of Geophysics

基　　金：国家重点基础研究发展计划(973计划)(2014CB744703);国家自然科学基金(41202189;41274005);地质灾害防治与地质环境保护国家重点实验室开放基金(SKLGP2014K009);中国博士后基金(2013M530412);中央高校基本科研业务费专项资金(2014G1261050;2014G3263014);中国地震局地震行业科研重点专项(201208009)联合资助

摘　　要：利用汾渭盆地及其邻域2001—2007年与2009—2011年高精度GPS监测资料,基于区域构造特点,采用块体运动应变模型结合数理统计假设检验法,建立了区域合理的地壳运动应变模型,基于此定量研究了区域现今地壳应变场及其变化特征,特别是2008年汶川强震对汾渭盆地区域变形特征的作用影响,同时从盆地整体上分析了盆地内多发的地裂缝灾害与区域整体构造变形特征之间的内在关系.研究结果表明:经统计检验判断,选择合理的区域地壳运动应变模型,对获取真实反映区域实际构造变形特性的应变参数具有重要的作用;2008年汶川强震对青藏东边缘地块及渭河盆地西侧局部地区应变场造成一定的影响,但是震后上述区域并没有出现显著的应变积累而是呈现出应变量值较震前减小的特征,分析其原因可能是因为此区域并不是强震造成的库仑应力显著增加区,在震后2009—2011年时间段内处于构造应力场的松弛调整期;汶川强震没有显著改变研究域现今整体的构造变形背景特征,区域地壳构造活动特征仍具有较好的继承性;基于研究域构造块体具有各向同性连续弹性变形的前提,初步推断整个汾渭盆地内多发的地裂缝灾害可能是区域NW—SE向拉张应力场作用下的地表破裂响应.The Fenwei basin is of great importance in research of tectonic activity and geological hazards（such as the ground fissures and earthquakes）in China.This basin is actually a deep riftthat divides North China into eastern and western parts.Bounded by the Qinghai-Tibet,Ordos,North China and South China blocks,the Fenwei basin is a accommodation zone of differential motions of these blocks,and the boundaries and decoupled strips of tectonics between western and eastern North China.We focused on the current crustal deformation characteristics of the Fenwei basin and its surrounding areas,especially the influence of the 2008 Wenchuan earthquake.Meanwhile,we further analyzed the intrinsic relationship between the tectonic deformation features of the overall Fenwei basin and the multiple ground fissures within the basin.Using high-precision GPS data for the periods of 2001—2007and 2009—2011from the projects＂Crustal Movement Observation Network of China＂and ＂Chinese Continental Tectonic Environment Monitoring Network＂,we have constructed reasonable crustal deformation models of the Fenwei basin and its surrounding areas based on the strain theory of the block movement combined with mathematical statistical hypothesis testing method. We then established the crustal deformation models of the Datong,Xinzhou-Taiyuan,Linfen-Yuncheng and Weihe basins,as well as the eastern Qinghai-Tibet and the northern edge of the South China blocks.Based on the strain results solved by these deformation models,the current crustal strain fields and their distribution characteristics were obtained,and the intrinsic relationship between the principal strain vectors of the overall Fenwei basin and the multiple ground fissures within the basin were discussed in detail.The results are as follows：（1）The deformation models after selection by hypothesis statistical testing can better describe the strain distribution characteristics,especially the inherent differences in the interiors of the basins or blocks.（2）During the per

关 键 词：汾渭盆地 GPS 块体运动应变模型 数理统计假设检验 地壳应变特征 地裂缝灾害 

分 类 号：P223[天文地球—大地测量学与测量工程]