甘肃省钻孔应变主方位角、主应变时空变化特征分析

Analysis of Temporal and Spatial Variation Characteristics of Borehole Strain Principal Azimuth and Principal Strain in Gansu Province

通过对甘肃省2016-2019年钻孔应变数据的分析,发现高台、安西、临夏、刘家峡台数据自洽相关系数较高,仪器可靠性高;静宁、天水台次之,差分矫正后相关系数提高,仪器较可靠;陇南台相关系数较低,差分矫正后相关系数变化小。在主方位角、最大最小主应变方面,安西、高台、刘家峡、临夏、静宁台处于长趋势拉伸状态,拉伸应力方位分别在北偏东90.06°、127.27°、102.18°、94.18°、51.39°附近波动;陇南、天水台的应力变化为长趋势的压缩状态和先压缩后拉伸状态,应力主方向分别在北偏东166.86°、167.31°附近变化。上述结果与区域构造应力变化在一定程度上切合。

Through the analysis of borehole strain data from 2016 to 2019 in Gansu Province,it is found that the self-consistent correlation coefficient of Gaotai,Anxi,Linxia and Liujiaxia seismic stations are higher,and the instrument reliability are higher,followed by Jingning Seismic Station and Tianshui Seismic Station.After differential correction,the correlation coefficient is higher,the instrument is more reliable,the Longnan Seismic Station correlation coefficient is lower,and the variation of correlation coefficient after differential correction is small.In terms of principal azimuth and maximum and minimum principal strain,Anxi,Gaotai,Liujiaxia,Linxia and jingningtai seismic stations are in the stretching state of long trend.The direction of tensile stress fluctuates around 90.06°,127.27°,102.18°,94.18°and 51.39°north by east,respectively.The stress changes of Longnan Seismic Station and Tianshui Seismic Station are the compression state with a long trend and the compression state first and then tension state.The main direction of stress changes around 166.86°and 167.31°north by east,respectively.These results are in some degree consistent with regional tectonic stress changes.