基于GPS观测的六盘山断裂震间闭锁特征研究

综合利用1999—2013年中国大陆构造环境监测网络GPS速度场与跨六盘山断裂布设的10个GPS连续站观测剖面, 基于块体-位错模型, 研究了六盘山断裂震间闭锁性质与滑动亏损的空间分布。 结果显示, 六盘山断裂震间闭锁具有明显的分段特征, 其中断裂南段的闭锁程度最强, 滑动亏损速率的平均值最大, 地震危险性最高; 断裂北段闭锁程度弱于南段, 但断层浅部的滑动亏损速率平均值最大, 应变积累速度快, 也具有一定的发震能力; 中段闭锁程度最弱, 滑动亏损速率最小, 发震可能性小于南段和北段。

Interseismic Locking Characteristics of the Liupanshan Fault from GPS Observation

Synthetically using GPS velocity field of China tectonic environment monitoring network in the period of 1999—2013 and a profile with 10 continuous GPS observation stations across the Liupanshan fault, this paper studies the interseismic locking characteristics and the spatial distribution of slip deficit rate of the Liupanshan fault based on block-dislocation model. The results show that the interseismic locking of the Liupanshan fault has obvious segmentation characteristics: the southern segment of the fault has the strongest degree of locking and the biggest average value of slip deficit rate, so its seismic hazard is highest. Although the northern segment of the fault has weaker locking degree than the southern segment, its average value of slip deficit rate of the shallow part of the fault is the biggest in the three segments. It is proved that the strain accumulation speed of the northern section is fast and it also has some possibility of earthquake occurrence. Both the locking degree and the slip deficit rate of the middle segment are small, so it has lower ability of earthquake occurrence than the southern segment and northern segment of the Liupanshan fault.