Research on the Dynamic Evolution of Deformation Field and the Acquisition of Seismogenic Information Before Lijiang Earthquake With Ms7.0

By using the integral dynamic adjustment of the "segmentation rate," this paper processes the leveling repetition measurement data of the Dianxi(western Yunnan)area since the 1980s,makes the fitting of the velocity surface for vertical deformation with multi-surface function,and splits information of the vertical deformation field.The dynamic evolution of the deformation field and vertical deformation information norm-shear deformation,extension deformation,volumetric deformation,and quasi acceleration,which are the distribution characteristics of variation,are studied by using the information split before the Lijiang earthquake with MS7.0(February 3,1996)in the north of the Dianxi(western Yunnan)leveling network.The results indicate that in Dianxi(western Yunnan)area,the acute vertical differential movement of the large-scale deformation velocity high gradient belt and high information norm distribution in the Lijiang,Yongsheng,and its adjacent areas in the middle stage of the 1980s is the reflection

丽江7.0级地震前形变场动态演化与孕震信息提取研究

本文用分段速率整体动态平差法，处理了滇西水准监测网８０年代以来的水准复测资料，并进行了形变速率多面函数拟合和垂直形变场信息分离。研究了１９９６年２月３日发生于滇西水准监测网北部的丽江７０级地震前，形变场动态演化和信息分离得到的垂直形变剪切变形、扩张变形、体积变化及准加速度等信息指标分布变化特征。结果表明：８０年代中前期，在滇西的丽江、永胜及其附近地区出现的大规模形变速率高梯度带和信息指标高值分布所反映的剧烈垂直差异运动，是丽江７０级地震前１０余年孕震应变能开始快速积累的显示；而１９８５～１９９２年形变场趋势转折与垂直差异运动显著减弱，可能意味着孕震能量积累到一定程度后，孕震区处于相对闭锁阶段。在此基础上，结合丽江７０级地震前区域地震活动分析和不同地区强震孕震形变对比，进一步研究了强震前形变场非均匀态特征和孕震信息的识别提取，得出了一些用大地形变进行强震中期预测的有益结果。