Summary The 2020 MS 5.0 Qiaojia earthquake occurred in a tectonically complex region near the Xiaojiang fault in southwestern China. We investigated the rupture process of this moderate-sized earthquake using a multi-empirical Green’s function (EGF) inversion method that integrated waveforms from multiple EGF events. Synthetic tests demonstrated that the multi-EGF inversion method recovered the input model more robustly than any individual EGF inversion. The resolved spatiotemporal rupture model of this earthquake indicated a compact rupture lasting approximately 2.9 s, dominated by a major asperity near the hypocenter and characterized by predominantly eastward rupture propagation. Bootstrap resampling analyses further confirmed the robustness of the resolved major coseismic slip distribution and the overall moment release pattern. We also observed a spatial complementarity between the coseismic slip and aftershock distributions, with most aftershocks clustering around the periphery of the major asperity. This study not only elucidates the source complexity of the 2020 MS 5.0 Qiaojia earthquake, but also validates the robustness and effectiveness of the multi-EGF inversion method in resolving the rupture processes of moderate-sized earthquakes. Our results provide new insights into the rupture kinematics of moderate-sized earthquakes and the heterogeneity of fault strength and stress within the Xiaojiang fault zone and its surrounding regions.
Zhang et al. (Fri,) studied this question.