安徽省钻孔应变典型干扰与地震短临异常特征分析  

ANALYSIS OF TYPICAL DISTURBANCE OF BOREHOLE STRAIN AND SEISMIC SHORT-TERM ABNORMAL CHARACTERISTICS IN ANHUI PROVINCE

作　　者：王燚坤[1] 郑海刚[1,2] 李军辉 汪小厉[1] 鲍子文 洪德全 赵朋[1] WANG Yikun;ZHEN Haigang;LI Junhui;WANG Xiaoli;BAO Ziwen;HONG Dequan;ZHAO Peng(Anhui Earthquake Agency,Hefei 230031,China;Mengcheng National Geophysical Observatory,Mengchen 233527,China)

机构地区：[1]安徽省地震局,安徽合肥230031 [2]蒙城国家地球物理野外站,安徽蒙城233527

出　　处：《高原地震》2020年第2期1-8,共8页Plateau Earthquake Research

基　　金：安徽省地震局“场带站”青年基金项目(项目编号:20190409)资助。

摘　　要：利用安徽省数字化钻孔应变观测资料,对气压、降雨和水位三种主要干扰因素的变化特征及影响机制进行了分析。以2倍均方差作为标准对M 2波潮汐因子进行异常提取,讨论了M≥4.0地震的短临异常特征。结果表明:气压短期波动变化会引起体应变固体潮畸变,在时间上往往表现为基本同步或滞后变化,长周期的气压缓变会对钻孔体应变趋势变化产生影响;降雨量大小和降雨持续时间长短对体应变的干扰程度不同,强降雨会使测值出现即时效应;钻孔应变与水位变化存在同步性,但在影响时间上明显滞后于水位变化。各地震台受气压、降雨和地下水位的影响存在差异性,钻孔应变观测点在裂隙、破碎带上受干扰更为显著。肥东地震台岩体破碎,其井孔对干扰具有放大作用,受气象因素和水位影响十分典型。嘉山、六安地震台钻孔体应变在地震前有1~3个月的潮汐因子异常,表现形态为上升—恢复型和突跳变化。Based on the borehole strain observation data in Anhui Province,the variation characteristics and influencing mechanism of three main interference factors,air pressure,rainfall and water level are analyzed in this paper.The anomaly extraction of M 2 waves tide factor is carried out by using twice mean square variance as the standard,and the short-term and imminent anomaly characteristics of M≥4.0 earthquakes within the prediction efficiency range of drilling strain are discussed.The results show that the short-term fluctuation of air pressure will cause the distortion of solid tide of body strain,which usually shows the basic synchronous or lag change in time,and the long-term slow change of air pressure will have an impact on the change trend of body strain of drilling hole.Different stations are affected by air pressure,rainfall and groundwater level,and the borehole observation points with fractured and broken zones are more significantly affected by interference.The strain of drilling body in Jiashan and Liuan station was abnormal for 1~3 months before the earthquake,and the pattern was ascending-restoring type and sudden jump change.

关 键 词：钻孔应变 典型干扰 潮汐因子 异常特征 

分 类 号：P315.725[天文地球—地震学]