Study on the Foreshock and Preseismic Anomaly of the MS5.5 Earthquake in Subei,Gansu Province
GAO Shude
YANG Xiaopeng
CHEN Yuxin
WU Shanyi
Abstract：On October 24,2023,the MS5.5 earthquake in Subei,Gansu Province occurred on the NWW-trending fault zone at the northern edge of the Qilian Mountains,with a thrust type focal mechanism.Before the earthquake,there were 5 seismic anomalies in the central and western sections of the Qilian Mountains.Among them,there was a new MS3 earthquake anomaly in the western section of the Qilian earthquake zone one month before the earthquake.In July 2023,the strain EW component of the Xigou Cave in Jiayuguan changed from tension to compression,and the NS component showed a decrease in annual amplitude.114 days later,54 km away from the measuring point,a MS5.5 earthquake occurred in Subei,Gansu Province.In the two days before the main earthquake,there was a significant increase in seismic activity in the southeast direction,with a total of 26 recorded earthquake events,the largest of which was Subei MS4.7 earthquake on October 22,2023.It entered a calm period about 7 hours before the main shock and then the main shock occurred.This paper summarizes the abnormal changes in various measurement items before Subei MS5.5 earthquake,as well as the experience accumulated in determining the occurrence of the main earthquake by determining the foreshock sequence,and adds new earthquake examples to earthquake prediction research.
Keywords：Subei MS5.5 earthquakePrecursor anomalyForeshockEarthquake prediction
Publication Date：2025-09-30
Online Publishing Date：2025-10-10(First online date of this platform, not the publication date of the document)
Pages：5( 1-5 )