门源6.9级地震前后高台钻孔倾斜异常特征分析

ABNORMAL ANALYSZS ON BOREHOLE TILT IN GAOTAL BEFORE AND AFTER MENYUAN M6.9 EARTHQUAKE

针对高台钻孔倾斜南北分量2021年10月14日出现的加速北倾异常,通过现场核实和现场比对实验认为人为干扰不是加速北倾主要原因。利用速率分析法、同震响应分析、相对速率分析法分析认为,此次加速北倾异常可信。异常持续2个月后发生门源6.9级地震,认为震前加速北倾与此次地震有关;震后异常形态持续且在祁连山西段出现同步形变异常,可能与后续发生的德令哈5.8级地震有关。综合分析认为,高台钻孔倾斜2021年10月14日以来出现的加速北倾异常对应2022年1月8日门源6.9级地震和德令哈1月23日5.8级、3月26日6.0级地震。

In view of the accelerated north dip anomaly of the NS component of the drilling slope on October 14,2021,it is believed that human interference is not the main reason for accelerated north dip in field verification and field comparison experiment.The rate analysis method,co-seismic response analysis and relative rate analysis method were used to show that the acceleration of the north dip was exceptionally credible.The Menyuan earthquake of magnitude 6.9 occurred two months after the anomaly,and the acceleration of the north dip before the earthquake was related to the earthquake.After the earthquake,the abnormal shape was sustained and there was a synchronous deformation anomaly in the western Qilian Mountains,which may be related to the subsequent Delingha M5.8 earthquake.According to the comprehensive analysis,the accelerated northward dip anomaly since October 14,2021 corresponds to the Menyuan earthquake of January 8,2022,and the Delingha M5.8 earthquake of January 23,and M6.0 of March 26,2022.