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The Xianshuihe fault is a large sinistral strike-slip fault connected with the Anninghe fault to the south and the Ganzi-Yushu fault to the north. It is located in the southeastern Tibetan Plateau, playing an important role in accommodating slip due to India's continued squeeze on Eurasia (

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The 2022 Ms 6.1 Lushan earthquake occurred in the southern segment of the Longmenshan fold-and-thrust belt, Sichuan Province, China, ∼7 km north-northwest of the 2013 Ms 7.0 Lushan earthquake. To understand its source characteristics and interplay with the 2013 Lushan event, we evaluate the 2022 Lushan earthquake in terms of focal mechanism, aftershock relocation, and rupture process. Results show that it is a purely thrust earthquake with a source depth of 14 km and a focal mechanism nodal plane of 29°/51°/80°. The automatic phase picker-based aftershock locus clarifies that the 2022 Lushan earthquake occurred on a blind northeast-trending conjugate fault of the 2013 Lushan earthquake. The finite-fault model constrained by teleseismic waveforms suggests that the high slip is concentrated in an asperity near the epicenter with a peak slip of 42 cm, which is characterized by thrust components. Based on the promotion of postseismic deformation following the 2013 Lushan earthquake and the similarity of the seismotectonic system, we argue that the 2022 Lushan earthquake may be an aftershock of the 2013 Lushan earthquake that occurred on a blind thrust fault.

The Xianshuihe (XSH) fault on the eastern boundary of the Tibetan plateau is one of the most active faults in the world. However, the Moxi fault, the southernmost segment of the XSH fault, remained seismically quiescent for over 230 yr, with a large slip rate and high locking degree. Thus, this region is considered to be a seismic gap capable of hosting earthquakes of Mw 7.0 or greater. In September 2022, the Ms 6.8 Luding earthquake occurred on the Moxi fault, resulting in destructive landslide damage, with 93 people dead and 25 missing. Using regional and global seismic recordings, we integrate the multiple-point-source analysis, finite-fault inversions, and backprojection imaging to investigate in detail the rupture process associated with the 2022 Luding, China, earthquake. Our results show that this event is characterized by an asymmetric bilateral rupture with three episodes: (1) an initial bilateral rupture propagation mainly toward north-northwest; (2) major rupture propagating toward south-southeast and up-dip direction; (3) south-southeast-rupture propagation speed accelerates to ∼2 km/s. Over 70% of the seismic moment is released at shallow depths <12 km thus explaining significant damaging effects. Furthermore, the seismic potential of the remaining locked portions of the XSH and Anninghe faults is still high and positive increases of the Coulomb stress on these faults due to the Luding earthquake might bring them closer to future failure.