Seismic Sensor Misorientation Measurement Using P‐Wave Particle Motion: An Application to the NECsaids Array
Seismic Sensor Misorientation Measurement Using P‐Wave Particle Motion: An Application to the NECsaids Array
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DOI：
10.1785/0220160005
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发表时间：
2016-07
影响因子：
3.3
通讯作者：
Xin Wang;Qi‐Fu Chen;Juan Li;S. Wei
中科院分区：
文献类型：
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作者：
Xin Wang;Qi‐Fu Chen;Juan Li;S. Wei
地震传感器方位是现代三分量地震观测最关键的参数之一。然而，这一参数很容易受到台站附近强磁异常或赤纬定标人为误差的影响。因此，在利用三分量波形数据之前，对传感器的定向误差进行检测和校正是非常重要的。在这项研究中，我们通过分析P波质点运动，测量了我们的临时地震台阵(东北中国深俯冲地震台阵，简称NECSAIDs)的时变传感器定向偏差。我们应用主成分分析和最小横向能量法研究了震中距在5°到90°之间的地震，以估计传感器的偏向。我们的结果与直接陀螺罗经的测量结果具有很高的一致性，相关系数为0.95。我们的统计分析表明，我们可以利用10个具有高信噪比记录和高度线性P波偏振的地震来估计稳健的传感器定向错误。我们还发现，各向异性或倾斜界面的影响产生了方位向后的周期性图案，对于我们的错误取向估计来说，这一影响相对较小。通过分析合成地震记录定向误差引起的幅度变化，并考虑各向异性和倾斜界面的影响，以及测量误差，我们期望工程师能够定位误差小于3°的地震传感器。
Seismic sensor orientation is one of the most critical parameters for modern three‐component seismological observation. However, this parameter is easily subject to error imposed by strong magnetic anomalies near the station or by human error in declination calibration. It is therefore very important to inspect and correct for sensor misorientation before utilizing three‐component waveform data. In this study, we measured the epoch‐dependent sensor misorientation for our temporary seismic array (NorthEast China Seismic Array to Investigate Deep Subduction, or NECsaids) by analyzing P ‐wave particle motions. We applied principal component analysis and the minimizing transverse energy method to study earthquakes with epicentral distance between 5° and 90° to estimate the sensor misorientation. Our results show high consistency with the direct gyrocompass measurements, with a correlation coefficient of 0.95. Our statistical analysis suggests that we can estimate robust sensor misorientation utilizing 10 earthquakes with high signal‐to‐noise ratio records and highly linear P ‐wave polarizations. We also find that the influence of anisotropy or a dipping interface produces a periodical pattern with back azimuth and is relatively small for our misorientation estimation. By analyzing the amplitude change of synthetic seismograms due to misorientation and taking into account the influence of anisotropy and dipping interfaces, as well as the measurement errors, we expect engineers to be able to orient seismic sensors with error smaller than 3°.