Abstract： On January 21, 2016, a strong earthquake with a magnitude of MS6.4 occurred at Menyuan, Qinghai province, China. In almost the same region, another strong earthquake occurred in 1986, with similar magnitude and focal mechanism. Based on comprehensive analysis of regional active faults, focal mechanism solutions, precise locations of aftershocks, as well as GPS crustal deformation, we infer that the Lenglongling active fault dips NE rather than SW as was suggested by previous studies. Considering the facts that the 2016 and 1986 MS6.4 Menyuan earthquakes are closely located with similar focal mechanisms, that both quakes are on the north side of the Lenglongling fault and adjacent to the fault, and that the fault is dipping in a NE direction, we suggest that the fault is the seismogenic structure of the two events. The Lenglongling fault, as the western segment of the well-known Tianzhu seismic gap in the Qilian-Haiyuan active fault system, is in a relatively active state with frequent earthquakes in recent years, implying a high level of strain accumulation and a high potential for a future major event. It is also possible that the Lenglongling fault and the adjacent Jinqianghe fault in the Tianzhu seismic gap, will rupture simultaneously in the future.
LI Yanbao,GAN Weijun,WANG Yuebing et al. Seismogenic Structure of the 2016 MS6.4 Menyuan Earthquake and Its Effect on the Tianzhu Seismic Gap[J]. jgg, 2017, 37(8): 792-796.
