2023年甘肃积石山6.2级地震前测震学异常特征分析

Characteristics of seismometric anomalies before the Jishishan,Gansu M_(S)6.2 earthquake in 2023

结合甘肃及其邻区地震活动特征,经系统梳理,发现在2023年12月18日积石山6.2级地震前出现的4项测震学异常:(1)甘东南地区4级地震平静;(2)祁连山地震带中段M L2.0以上地震活动连续三个月增强;(3)甘肃夏河至内蒙古鄂托克前旗3级地震条带的出现;(4)甘青川交界3级地震空区。通过震例回溯,总结此次地震异常指标的预测意义。分析认为,地震平静、空区、条带3项异常对本次地震的发震位置具有较好的指示;祁连山地震带中段M L2.0以上地震活动连续三个月增强对本次地震的发震时间具有较好的指示,具有短期预测意义。

Based on the characteristics of the seismic activity in and around the Gansu region,this paper systematically organizes the seismometric anomalies before the M_(S)6.2 Jishishan earthquake,which occurred on December 18,2023.These anomalies were as follows:seismic quiescence(M S≥4.0)in southeastern Gansu,constant enhancement of seismicity(M L≥2.0)in the central Qilian Mountain seismic zone for more than three months,seismic band of M S3.0 earthquakes between Xiahe in Gansu and Otog Qianqi in Inner Mongolia,and a seismic gap of M S≥3.0 earthquakes in the bordering region of Gansu,Qinghai,and Sichuan.Through the retrospection of these earthquakes,the prediction meaning of the abnormal indexes was summarized.It is considered that factors such as seismic quiescence,seismic gap,and seismic band are good indicators of the location of the Jishishan M_(S)6.2 earthquake and the continuous enhancement of seismicity(M L≥2.0)in the central part of the Qilian Mountain seismic zone is a good indicator of the occurrence time of this earthquake.A comprehensive analysis of the seismometric anomalies can provide an effective judgment basis for earthquake predictions.