Analysis of Seismic Activity Variation before the Pingshan M_S4.3 Earthquake in Hebei Province

The Pingshan M_S4.3 earthquake occurred in a weak earthquake area on October 3, 2022. It is the largest earthquake within 50 km of the periphery since 1970. In order to quantitatively analyze the variation of seismic activity before the Pingshan M_S4.3 earthquake, We improved the “Region-Time-Length” (RTL) algorithm, increased the weight of the seismic events close to the node in distance and time, and decreased the weight of seismic events that are far away from the node in distance and time. We used the improved RTL algorithm to scan the V_\rmRTL time curve of the epicenter and the evolution image of regional V_\rmRTL value, respectively. The results show that there are seismic quiescence anomalies in the west and southwest of the epicenter before the Pingshan M_S 4.3 earthquake. At the same time, there are seismic quiescence anomalies in the south of the epicenter before the Pingshan M_L3.5 earthquake on February 23, 2020. The characteristic distance and the lower limit of magnitude have a certain influence on the scanning results, and the characteristic distance has a greater influence on the scanning results in the area with complex seismic activity. The RTL algorithm can quantitatively analyze the variation of seismic activity and provide methods and basis for the tracking of seismic situation and seismic risk analysis in weak earthquake areas.