Using real and synthetic waveforms of the Matata swarm to assess the performance of New Zealand GeoNet phase pickers
Using real and synthetic waveforms of the Matata swarm to assess the performance of New Zealand GeoNet phase pickers
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使用 Matata 群的真实波形和合成波形来评估新西兰 GeoNet 相位选择器的性能
DOI：
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发表时间：
2013
期刊：
影响因子：
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通讯作者：
Kris Gledhill
中科院分区：
文献类型：
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作者：
S. J. Rastin;C. Unsworth;R. Benites;Kris Gledhill
摘要我们通过比较2008年新西兰马塔塔地区当地地震序列的真实的地震图和相应的合成地震图，评估了新西兰地震台网（NSENN）的P-和S-相位拾取器的性能。我们通过计算85个假设台站的合成地震图，研究了辐射方向图对拾取器性能的影响。它们位于距离震源10、20、30、40和50 km处，震源由双力偶点源表示。与P相起始相比，在每个距离处，拾取的S相起始与平均拾取起始的偏差更大。每个点与平均P相起始点的偏差不影响与平均S相起始点的相应偏差。我们确认，在2008年没有一个关键站位于拾取误差大或相位错过由于辐射模式。我们还研究了在三种不同信噪比水平（SNR=20、10和3 dB）下噪声对拾取器性能的影响。当SNR为3 dB时，在50 km距离处未拾取P相起始时间。两台采摘机在距离震源20公里的站点上表现一致。在更大的距离上，方位角为0°、21°和339°的三个海基观测点在噪声水平增加的情况下表现出一致的性能。在线材料：描述拣选机性能的表格，无噪声合成数据。
Abstract We assess the performance of the P ‐ and S ‐phase pickers of the New Zealand Seismograph Network (NZSN) by comparing their outputs for real seismograms and corresponding synthetic seismograms of the local earthquake sequence in the Matata region, New Zealand, during 2008. We study the effect of the radiation pattern on the pickers’ performance by computing synthetic seismograms at 85 hypothetical stations. These are located at distances of 10, 20, 30, 40, and 50 km from an earthquake source represented by a double‐couple point source. The picked S ‐phase onset has larger deviations from the mean picked onset at each distance compared to the P ‐phase onset. Deviation from the mean P ‐phase onset at each point does not affect the corresponding deviation from the mean S ‐phase onset. We confirm that none of the key stations in 2008 are located where the picking errors are large or where the phases are missed due to the radiation pattern. We also study the effect of noise on the pickers’ performance at three different signal‐to‐noise ratio levels (SNR=20, 10, and 3 dB). No P ‐phase onset time was picked at 50 km distance when SNR was 3 dB. Both pickers had a consistent performance at stations with 20 km distance from the earthquake source. At larger distances, three sea‐based observatory points with azimuth angles 0°, 21°, and 339° show a consistent performance in the presence of the increased noise level. Online Material: Tables describing the performance of the pickers with noise free synthetic data.