基于GPS和小震研究金沙江断裂带现今活动特征

Study on Current Activity Features of Jinshajiang Fault Zone Based on GPS and Small Earthquakes

利用GPS水平速度场和现今小震活动分布资料,对金沙江断裂带活动特征开展分段分析,并对其地震危险性进行讨论。结果表明:1)金沙江断裂带不同段落的活动性存在差异,北段活动性不明显,中段及南段表现出明显的右旋走滑运动,滑动速率分别为4.9 mm/a和5.5 mm/a,闭锁深度约为20 km;2)金沙江断裂带中段及南段存在应变积累,地震危险性不容忽视;3)从现今地壳形变资料分析,金沙江断裂带是控制川滇菱形块体运动的西北边界。

In this paper,we analyze the characteristics of segmental activity on the Jinshajiang fault zone using GPS horizontal velocity field and current small earthquake activity distribution data,and discuss the seismic risk.The results show that:1)The activity of the Jinshajiang fault shows segmentation characteristics.The activity in the northern section is not obvious,but the middle and southern sections show obvious right-lateral strike-slip movement.The sliding rates are 4.9 mm/a and 5.5 mm/a respectively,and the blocking depth is about 20 km.2)There are strain accumulations in the middle and south sections of the Jinshajiang fault,and the seismic risk cannot be ignored.3)According to current crustal deformation data,the Jinshajiang fault is the northwestern boundary that controls the movement of the Sichuan-Yunnan rhombus block.