利用P波质点运动估算中国东北地区固定台站地震计方位角  

Component azimuths of the permanent seismic stations in the Northeast China estimated from P-wave particle motion

作　　者：韩光洁 邓文泽 杨志高[1] Han Guangjie;Deng Wenze;Yang Zhigao(China Earthquake Networks Center,Beijing 100045,China)

机构地区：[1]中国地震台网中心,北京100045

出　　处：《地震学报》2024年第1期81-91,共11页Acta Seismologica Sinica

基　　金：国家自然科学基金(42304072);地震科技星火计划(XH23050YB)联合资助。

摘　　要：现代地震研究依赖于可靠的三分量观测数据,地震计的北分量是否严格指北将直接影响研究的准确性。然而,受台站附近磁异常或人为安装错误的影响,地震计的方位角可能出现偏差。基于东北地区154个固定台站2020年的远震数据,利用P波质点运动方法,估算了每个台站的北向分量方位角,以判断台站地震计是否存在方位角偏转问题。结果表明,84%的台站运行良好,12%的台站存在方位角偏差绝对值过大(>20°)或分量极性反转等问题。此外,分析后发现方位角偏转较大会导致H-κ叠加方法计算得到的地壳厚度和地震波速比出现偏差。因此,为确保地震学分析的可靠性,固定台站的地震计方位角需要进行定期校标。Modern seismic studies rely on reliable three-component seismological observations,whether the station sensor's north component strictly aligns to the geographical north or not will directly affect the accuracy of the research.However,due to magnetic anomalies near the station or artificial error,the azimuth of seismometer may be deviated.In this study,the component azimuths of 154 permanent seismic stations in Northeast China were rechecked using the P-wave particle motions based on the teleseismic events in 2020,and we used the same seismic events to calculate the component azimuth by the principal component analysis and the signal-to-noise-weighted-multievent method,respectively.The azimuth deviation determined by these two methods are very consistent,with a correlation coefficient of 0.998 6.Among the 154 stations,the azimuth of 84% of the stations deviate slightly from the true north,and some of the stations have some sort of problems,including azimuth deviation of the two horizontal components(>20° or <-20°) or polarity reversal in one or more components.We found a large deviation in sensor azimuth could result in incorrect estimatiog of both crustal thickness and v P/v S ratio by H-κ stacking.Therefore,in order to ensure the reliability of seismological analysis,the azimuth of the station needs to be checked and calibrated regularly.

关 键 词：方位角 P波质点运动 地震计 东北地区 H-κ叠加 

分 类 号：P315.78[天文地球—地震学]