Abstract:A large earthquake occurred at Luojiabu town, between the two cities of Tianshui and Lixian in the south of Gansu Province on July 21, 1654, that is, June 8-the eleventh year of Shunzhi in the Qing Dynasty. It is called the Southern Tianshui earthquake with magnitude about 8. This paper simply reviews the research history of the Southern Tianshui M8 earthquake in 1654. Then, according to the original historical earthquake data and new data by additional investigation in recent years, we check the intensities of the destoried sites, and then modify the seismic isoseismal line again, where the long axis is about the NE direction. This earthquake caused a large area of the town wall to collapse, civilian houses were ruined, and a large number of people died or were injured. It also caused serious seismic-geological disasters, such as landslips, rock collapses, and sag lakes. The epicenter area was located in the area from Yongxing, Luojiabu to Tianshui town along the valley of the western Hanshui River, west of Lixian county city. This area developed an active fault in Holocene, the Lixian-Luojiabu fault, which is characterized by left-lateral strike-slip faulting by normal components. According to recent field investigations, there are some earthquake rupture traces, such as seismic fault scarps, small valley left-lateral offsets, and seismic fault grooves along the Lixian-Yanguan-Luojiabu segment of the fault. The location of the earthquake rupture is consistent with the heavily-damaged area affirmed by historical textual criticism data, and confirmed both of them the reliability and rationality of the results.
