Abstract: The earthquake sequence’s spatial-temporal evolution can help to reveal the earthquake nucleation process and the interaction between earthquakes. In this paper, we relocated earthquakes in the catalog since 2009 around the 2022 Menyuan M_S6.9 focal area with the HypoDD and used them as templates to match-filter re-scan continuous waveforms, building a more complete seismic activity map before and after the mainshock. The results show there was not obvious foreshock pefore the 2022 Menyuan mainshock and it was a typical mainshock-aftershock sequence. Most of aftershocks mainly occurred in a strike-slip fault on the south side of Tuoleshan-north fault, dipping to the south at a high angle. The early aftershocks expanded along strike to the east and west with a logarithm migration relationship between distance and the elapsed time, meeting the rule of the afterslip expansion. The Lenglongling fault oblique intersects with the mainshock’s fault, and its seismicity is different from the aftershocks. The events in the Lenglongling fault occurred before the aftershock expansion front and migrated southeastward along the strike, but soon blocked. The migration continued again only after the M_S5.2 earthquake occurred 5 days later, and finally stopped near the end of the 2016 Menyuan aftershock zone. Therefore, the spatial-temporal evolution pattern of the earthquakes indicates the two faults interaction and the seismicity in the Lenglongling fault is probably triggered by the Coulomb stress change from the 2022 Menyuan mainshock.

Key words: The 2022 Menyuan M_S6.9 earthquake, Microseismic detection, Earthquake relocation, Aftershock migration, Earthquake triggering