Characteristic Analysis of the MS6.0 Ma'erkang Earthquake Sequence on Jun. 10, 2022

Abstract

On June 10, 2022, the MS6.0 Ma'erkang earthquake sequence occurred in the Bayan Har block. In this paper, the temporal and spatial distribution and attenuation characteristics of earthquake sequence is analyzed based on the regional structure, the temporal and spatial distribution of earthquake sequence, the focal mechanism solution, and the parameters of earthquake sequence, using the data of Sichuan Seismic Network and the temporary stations incorporated into the network. The results show that: (1) The MS6.0 Ma'erkang earthquake sequence is generally distributed in NW-SE direction, and the long axis of this series is basically consistent with the nearby Songgang fault. (2) As the earthquake sequence is formed by three large events with MS ≥5.0, the frequency of small earthquakes in the earthquake sequence area generally attenuates relatively slowly, while the activity level (magnitude) of aftershocks attenuates rapidly. (3) After the MS5.2 earthquake, the sequence parameters obtained show that the h-value is 1.09 and the p-value is stable at 1.02, indicating that the intensity and frequency attenuation of the earthquake sequence are gradually stable and tend to be normal. The b-value is 0.95, indicating that the maximum aftershock magnitude of the series is estimated to be ML5.1, and the b-value gradually tended to be stable, indicating that the stress in the region gradually tended to be balanced after the MS5.2 earthquake. The MS4.4 (ML5.0) earthquake that occurred at 4:37 on June 10 (local time) is the largest aftershock after the MS5.2 earthquake in the sequence. (4) The Songgang fault with NW-SE trend is presumed to be the main seismogenic tectonics, but the migration of three earthquakes with MS≥5.0 may also indicate that the Songgang fault is not a single seismogenic tectonics, which requires further field scientific investigation and analysis.