Abstract:
Based on the waveform data observed by the near field strong-motion stations, the earthquake rupture process can be quickly and stably inverted. This paper collected waveform data recorded by the strong-motion stations reconstructed in Qinghai during the implementation of the National Rapid Intensity Report and Seismic Early Warning Project. Based on these data, the rupture process of the
MS6.9 Qinghai earthquake on January 8, 2022 was inverted by the iterative deconvolution and stacking (IDS) method. The rupture model from inversion shows that the rupture extends from the initial rupture point to a unilateral rupture in the southeast-east direction, with a duration of about 14 seconds (mainly focus on 2−8 seconds), a maximum slip of 3.6 m, and a rupture length of about 20 km. This suggests that the rupture extends longitudinally from the deep to the shallow, which is consistent with the surface rupture found in the field investigation. The spatial distribution of aftershock sequences shows significant segmentation characteristics, indicating complex tectonic transitions in the rupture zone. There is still the possibility of strong earthquakes in this area in the future.