滇西区域水准观测的负位错反演与应变积累分析

利用1981～2006年滇西地区5个时段的区域水准观测资料,借助负位错模型反演,参考典型大震应力触发计算及跨断层等形变观测结果,研究了活动块体边界断裂应变积累的状况、分段差异性、时空演变及其与强震孕育—发生过程的关系。结果表明,该区6级以上地震多发生在断裂强锁定段或锁定程度显著加强段及其附近;目前宾川—南华以南、南涧以北,洱源、丽江一带可能反映相对较高的应变能积累背景,南定河断裂附近反映一定程度的应变积累特性。

Inversion of Negative Dislocation for Regional Level Observation and Analysis of Strain Accumulation in West Yunnan

We used negative dislocation model to inverse the 1981~2006 regional level observation data of West Yunnan on the basis of the stress triggering computation and across-fault observation data,thus studying the strain accumulation status and difference of the tectonic blocks' boundary faults,the time-space evolution and the relationship with the process of the development and occurrence of strong earthquakes.The result shows:(1)in this area,most earthquakes with magnitude over 6 occurred on the locked segments or obviously enhanced locked segments of the blocks' boundary faults and nearby;(2)presently the region south of Binchuan-Nanhua and north of Nanjian and the region from Eryuan to Lijiang reveal the background of obvious strain accumulation,while around the Nandinghe fault appears the strain accumulation to some degree.