1654年甘肃礼县8级地震发震断裂研究

1654年礼县8级地震的发震区地处新构造活动强烈的青藏高原东北缘,位于南北地震带中北段,发育多条活动断裂。礼县8级地震发生在黄土覆盖区,距今约370年,受自然侵蚀与人类活动的影响,其地表破裂带和次生灾害现在已经难以分辨。为此,文章收集整理了1970年以来的地震台网和流动台网观测资料,基于地震层析成像方法,经过联合反演计算,研究1654年礼县8级地震的发震构造。研究根据岷县—礼县—两当一线的小震活动分布,推测存在"岷县—礼县—两当断裂",可能是1654年礼县8级地震的发震断裂,但仍需野外地质工作的进一步研究。

Seismogenic fault study of the 1654 M8 Lixianearthquake in Gansu Province

The 1654 Lixian M8 earthquake occurred in the northeastern margin of the Qinghai-Tibet Plateau with strong Neotectonic activity.The earthquake stricken area is located in the mid-north segment of the South-North seismic belt,where many active faults are developed.The M8 earthquake occurred in the loess area about 370 years ago.Affected by natural erosion and human activities,its surface rupture zone and secondary disasters are now difficult to distinguish.Many seismologists have done a lot of research work on the earthquake,and there are different understandings and opinions on its seismogenic fault.Therefore,based on the observation data of seismic network and mobile network since 1970,this paper studied the seismogenic structure of the Lixian M8 earthquake in 1654 by using the seismic tomography method and joint inversion calculation.According to the distribution of small earthquake activities along the Minxian-Lixian-Liangdang line,it was speculated that the"Minxian-Lixian-Liangdang fault"may be the seismogenic fault of the Lixian M8 earthquake in 1654,but further study of field geological work is still needed.