摘要
采用趋势曲面拟合和统计方法研究了汶川地震前1999～2007年区域网的应变积累,寻找震中的大致区域。除了昆仑山口西大地震震中及其周围地区外,2004～2007年震前区域网的应变积累的趋势曲面拟合表明,汶川地震发生在中国大陆第一剪应变积累大、范围最广的区域的东侧。应变分量的统计分析表明,震前,其分布在此区域及其附近同样有明显的异常,剪应变和面膨胀积累均增强。震前,震中周围的GPS连续观测站30s采样率的单历元解表明,震前地壳运动还有临震异常,特别是有垂直位移异常。
The methods of both best fits by trend surfaces and statistics are used in the aim of looking for the epicentral area from the strain accumulations in the regional network observed from 1999 to 2007 before the Wenchuan Earthquake. Besides the epicentral area of the Kunlun Mountain earthquake of MS. 1 in 2001, the results of best fits by trend surfaces of the strain accumulations from 2004 to 2007 in the regional network before the earthquake show that the Wenchuan earthquake occurred at the eastern fringe of a region of large area and large accumulations of the first shear strains and also at the northeastern fringe of a smaller region with significant areal compression accumulations. The statistics of the accu- mulations of the strain components show that they also show anomalous distribution patterns in this region and its neighborhood with increasing accumulations of both shear strain and areal compression. Positioning solutions of single epochs for continuous GPS observations in or around the earthquake area before the event show that there were eminent precursory crustal movements, particularly vertical movements.
出处
《武汉大学学报（信息科学版）》
EI
CSCD
北大核心
2009年第11期1336-1339,1349,共5页
Geomatics and Information Science of Wuhan University
基金
国家科技支撑计划重点资助项目(2006BAC01B02-02-05)
地震预测研究所基本科研业务专项资助项目(0207690239)
关键词
汶川大地震
地壳运动
GPS
地震预测
时间序列
同震位移
great Wenchuan earthquake
crustal movement
GPS
earthquake prediction
time- series
coseismic displacement
