[关键词]
[摘要]
基于九寨沟7.0级地震前后,震中区周缘和巴颜喀拉地块周缘的跨断层观测、大面积水准测量、地震活动性等资料,利用断层三维活动量参数和水准平差计算方法,综合分析了地震前后区域地壳形变以及巴颜喀拉地块整体性运动与地震间的关系。结论如下:①九寨沟地震前后,远场的西秦岭构造区、六盘山断裂带、龙门山断裂带和鲜水河断裂带上的跨断层流动场地出现不同程度的异常变化,震中区域的形变并不显著;②由巴颜喀拉地块周缘的断层异常活动和地震活动性分析可知,巴颜喀拉地块整体性的SE向顺时针加速运动,造成了九寨沟地震震中区域的应力积累,同时,包括芦山地震在内的几次强震对九寨沟地震有一定促震作用;③九寨沟地震后,区域应力积累得到一定程度的释放,应力可能会在“三岔口”区域加速积累。
[Key word]
[Abstract]
Based on cross-fault observation data, large area leveling data and seismic activity data of the periphery of epicenter area and Bayanhar block around the Jiuzhaigou MS7.0 earthquake, and 3D fault activity parameters and leveling adjustment calculation method, we analysed comprehensively regional crustal deformation before and after earthquake and the relationship between the Bayanhar block integrity movement and earthquake. The conclusions are as follow:① Before the Jiuzhaigou earthquake, there were abnormal changes in varying degrees in the west Qinling Mountain fault zone, the Liupan Mountain Fault zone, the Longmen Mountain Fault zone and the Xianshuihe fault zone, and the deformation in the epicentral region was not significant. ② Through the analysis of the fault activity and seismicity anomalies around the Bayanhar block, the block SE clockwise accelerated motion caused the stress accumulation of epicentral region, and then the earthquake occurred. At the same time, several strong earthquakes including Lushan earthquake has a certain accelerating effect on the Jiuzhaigou earthquake;③After the Jiuzhaigou earthquake, the regional stress accumulation has been released to some extent, and the stress may accelerate accumulation in the "three road" area.
[中图分类号]
P315
[基金项目]
中国地震局“三结合”项目(CEA-JC/3JH-163704)、中国地震局监测预报司专项(17A37ZX228)和科技部基础性工作专项(2015FY210400)共同资助