【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。更多还原

【Abstract】 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.The density change images of underground materials were obtained with 3D inversion combining the model of body 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 decreasing-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 decreasing-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.更多还原