2012年甘肃金塔Ms5.4级地震发震构造讨论

Discussion on Seismogenic Structure of Jinta Ms5.4 Earthquake in Gansu Province, 2012

摘要:

归纳总结了2012年甘肃金塔M_s5.4地震的基本参数,烈度分布、震害特征和发震构造背景等基本特征。此次地震发生在甘肃北山地区,新构造活动不明显,属构造稳定的地区。地貌上为戈壁丘陵区,震区无居民点,没有造成明显破坏。通过野外地质调查,发现了许多基岩崩塌现象,有些作为路标或导航用的石堆被震倒,其排列方向为NW向。利用震源机制解、余震分布方向和断层活动性调查资料综合分析,认为2012年金塔5.4级地震,是马山南东断层和神螺山一野马井断层共同作用的结果,其发震断层可能为神螺山-野马井断层。

Abstract:

Basic characteristics of Jinta M_s5.4 earthquake in 2012 such as earthquake parameters, distribution of intensities, damage characteristics and seismogenic structures are concluded in this paper. This event occurred at Beishan, the boundary of Jinta in Gansu and Ejinaqi in Inner Mongolia. It is a tectonically stable area for the neotectonic activity here is very weak. The landscape here is mainly made up by gobi desert and small hills, and there is no residential area, so the earthquake did not cause significant damage. In the field geological study, we found a lot of bedrocks collapse, some of which were fell down as signposts or cairns and their orientation was North-West. Based on a comprehensive analysis of focal mechanism, distribution of aftershocks and recent fault activities, we suggest that Jinta M_s5.4 earthquake was caused by the combined action of southeast Mashan fault and Shenluoshan-Yemajing fault. The causative fault should be Shenluoshan-Yemajing fault.