丽江7.0级地震前后地壳密度动态变化三维反演  

ON 3D INVERSION FOR CRUSTAL DENSITY CHANGE BEFORE AND AFTER LIJIANG Ms7.0 EARTHQUAKE

作　　者：玄松柏[1,2,3] 申重阳[1,2] 李辉[1,2] 

机构地区：[1]中国地震局地震研究所,武汉430071 [2]地壳运动与地球观测实验室,武汉430071 [3]武汉大学测绘学院,武汉430079

出　　处：《大地测量与地球动力学》2010年第1期14-20,共7页Journal of Geodesy and Geodynamics

基　　金：国家"十一五"科技支撑计划(2006BAC01B02-02);中国地震局地震研究所所长基金(IS200856060)

摘　　要：利用滇西实验场1994—1996年6期重复重力观测数据,经平差处理得到重力场差分动态变化,运用块体生长模式和遗传反演方法反演了该区地下物质密度的变化。结果表明:该区地下物质密度变化图像基本反映了丽江7.0级地震前后震中南部区域地下物质密度动态演化过程;近震中区地震前后密度变化趋势为减小-加速减小-减速减小-发震-增大-加速增大;震源区南部地震前后密度变化经历了相对稳定-增大-减小-加速减小-发震-增大的过程,证实了震前存在扩容机制。The repeated gravity data of western Yunnan in 6 terms from 1994 to 1996 were used to calculate the dynamic change of gravitational differentiation by means of adjustment. materials were obtained with 3 D inversion combining the model of body The density change images of underground growing and genetic algorithm. The results show that the regional density change images basically reflect the dynamic evolution process of medium density before and after the Lijiang Ms 7.0 earthquake in the south central region of epicenter;decreasing-accelerated decrea- sing- decelerated decreasing-earthquake- increasing- accelerated increasing is the trend of density change before and after the earthquake in the region of epicenter and relative stabilization-increasing-decreasing-accelerated decrea- sing-earthquake-increasing is the progress of density change before and after the earthquake in the southern of epicenter region,it proves that there is the mechanism of volumetric dilatancy before earthquake.

关 键 词：丽江地震 重复重力测量 密度变化 三维反演 扩容 

分 类 号：P315.3[天文地球—地震学]