井下地震观测能够避开地表的各种干扰,有效提高地震观测信号的信噪比。井下宽带地震计的安装方位角可以是任意方位的,需要通过对比地表标准地震计的安装方位来进行校正。本文提出一种窄带滤波优选检测方法,同时计算两台地震计NS方向和EW方向的相对方位角和相关系数,通过优选相对方位角度差不大于1.2°且相关系数大于0.995的计算结果进行平均计算,可以快速得到两台宽带地震计之间的相对安装方位角。通过对河南睢县地震台和内蒙古伊春地震台安装现场记录的地震信号和地球脉动信号进行对比,验证了窄带滤波优选检测方法是可行的。该方法的优点是可以用一晚的记录数据来计算得到两台地震计之间的相对方位角,该方法可用于井下宽带地震计安装时的方位校正,也可以用于地表地震计之间对齐误差的测试。

Borehole seismic observation has the advantage of avoiding various types of surface interference,thereby significantly improving the signal-to-noise ratio of seismic observation signals. However,the installation azimuth of borehole broadband seismometers is arbitrary and must be corrected by comparing it to the installation azimuth of surface standard seismometers. This paper proposes a narrowband filtering optimal detection method for this purpose,which simultaneously calculates the relative azimuth and correlation coefficient in the north-south and east-west directions between the two seismometers. By selecting the results where the relative azimuth angle difference is within 1.2° and the correlation coefficient exceeds 0.995,an average is calculated,allowing for a quick determination of the relative installation azimuth between two broadband seismometers. The feasibility of the narrowband filtering optimal detection method is verified through a comparison of earthquake signals and Earth pulsation signals recorded at the Suixian Seismic Station in Henan Province and the Yichun Seismic Station in Inner Mongolia. The key advantage of this method is its ability to calculate the relative azimuth between two seismometers using just one night of recorded data. This makes it highly effective for azimuth correction during the installation of borehole broadband seismometers and can also be used to test alignment errors between surface seismometers.

P315

中国地震局地震预测研究所所长基金(CEAIEF2022030104)、国家重点研发专项(2022YFC2204301)共同资助