井下地震计方位角检测技术应用研究  

Research on the application of borehole seismometer azimuth detection technology

作　　者：李少睿[1] 毛国良[2] 王党席[1] 罗治国[1] 

机构地区：[1]陕西省地震局,西安710068 [2]河北省地震局,石家庄050021

出　　处：《地球物理学报》2016年第1期299-310,共12页Chinese Journal of Geophysics

基　　金：中国地震局测震台网青年骨干培养专项(20140329)资助

摘　　要：本文利用波形相关分析法对井下地震计方位角检测精度及一致性进行分析研究.研究中在地表布设地震计进行不同距离、不同频带多套地震计方位角检测对比测试,并在四川泸州、宁夏灵武、陶乐、河南安阳、清丰、陕西定边等6个分别安装井下甚宽频带、宽频带、短周期地震计的台站,进行地表同台址不同频带多套地震计与井下地震计方位角检测及一致性对比测试.根据全球噪声模型1-10s之间存在明显的噪声峰值的特点,对测试数据进行0.2-0.3Hz带通滤波和仿真处理,通过分析得出,对于不同地震计组合,测试地震计方位角检测结果一致性较好,根据地表不同距离、不同频带地震计组合的检测精度和地脉动记录的特点,认为井下地震计方位角检测精度优于4°.Borehole seismic observation can effectively reduce the impact of ground noise,and improve the observation accuracy of micro seismic events.At present,there are more than 180 borehole seismic stations in China,covering observations from very broad band to short period.Orienting equipment such as gyroscope is generally used in the installation of a borehole seismometer to determine its azimuth.Due to the difference between borehole and surface observation,it is difficult to verify the actual horizontal azimuth of a borehole seismometer directly using agyroscope or other orienting equipment.A correlation analysis method was used in the azimuth detection of a borehole seismometer.To confirm its reliability and consistency,we first made comparison test of a set of seismometers on the surface with different frequency bands.And then,another comparison test was made on a set of seismometers with different distances apart from each other to verify the result accuracy and correlation coefficient variation trend on different bands and apart distances.We assume that it should be true also in the case of correlation analysis between borehole and surface seismometers.Finally,multiple sets of surface and borehole seismometers comparison tests were made,and their result reliability and consistency are discussed also.Test results at 3 ground surface experiment sites ZOZT,XAN and QLIT,show thatmeasuring cases with the same device distance but different frequency bands may yield azimuth and correlation coefficient with good consistency.As distance between compared devices increased,the bias of estimated azimuth relative to the real one increased,and the correlation coefficient decreased.For the experiment with device distance of 220 m,the root mean square error（RMSE）of estimated azimuths to the true case is less than 1 degree,the averaged correlation coefficient is about 0.97.For the experiment with device distance of 2514 m,the RMSE of estimated azimuths is less than 3.4degree,and the correlation coefficients vary from0.84 to

关 键 词：井下地震计 相关分析 地震计方位角 均方根误差 检测精度 

分 类 号：P631[天文地球—地质矿产勘探]