高台四分量钻孔应变对甘州5.0级地震的响应变化分析  

Analysis of Response Variation of Four-component Borehole Strain of Gaotai to Ganzhou M_(s)5.0 Earthquake

作　　者：李娜 冯建刚 武善艺 LI Na;FENG Jian-gang;WU Shan-yi(Gansu Earthquake Agency,Gansu Lanzhou 730000,China)

机构地区：[1]甘肃省地震局,甘肃兰州730000

出　　处：《防灾减灾学报》2022年第2期16-23,共8页Journal of Disaster Prevention And Reduction

基　　金：中国地震局兰州地震研究所地震科技发展基金青年基金(2019Q04)。

摘　　要：2019年9月16日张掖甘州5.0级地震前,高台YRY-4钻孔应变NE、NW分量自4月起至7月呈现压缩变化,打破以往转折上升的正常年变形态,经现场核实认为异常形态与仪器自身、周边干扰以及降雨等因素无关,作为前兆异常进行跟踪。地震发生时高台钻孔应变记录到同震效应,四分量面应变相关系数自震前、震中至震后有下降—上升的变化,地震结束后四分量钻孔应变逐渐恢复往年变化形态,面应变相关系数也逐渐恢复。因此高台钻孔应变NE、NW分量自4月中旬出现的破年变异常反映的就是此次甘州5.0级地震的前兆异常信息。Before the M5.0 Zhangye Ganzhou earthquake on September 16,2019,the strain NE and NW components of Gaotai four drilling hole showed compression changes from April to July,breaking the normal annual pattern of turning and rising in the past.After field verification,it was believed that the abnormal morphology had nothing to do with the instrument itself,surrounding interference and rainfall and so on,and was tracked as the precursor anomaly.On the day of the earthquake,the coseismic effect was recorded in the borehole,and the correlation coefficient of the surface strain of the four components decreased to increase from before and after the earthquake.After the earthquake,the correlation coeffici-ent of the surface strain of the four components gradually recovered to the pattern of the previous years,and also gradually recovered.Therefore,the abnormal breakage of NE and NW components of Gaotai borehole strain since mid-April reflects the precursor anomaly information of this M5.0 earthquake in Ganzhou.

关 键 词：高台钻孔应变 破年变 面应变相关系数 甘州5.0级地震 

分 类 号：P315.72[天文地球—地震学]