Support Vector Machine Classification of Seismic Events in the Tianshan Orogenic Belt
Support Vector Machine Classification of Seismic Events in the Tianshan Orogenic Belt
复制标题
天山造山带地震事件的支持向量机分类
DOI：
10.1029/2019jb018132
复制
发表时间：
2020-01-01
影响因子：
3.9
通讯作者：
Wen, Lianxing
中科院分区：
文献类型：
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作者：
Tang, Lanlan;Zhang, Miao;Wen, Lianxing
区分不同类型的地震事件具有重要的科学和社会意义。本文采用支持向量机（SVM）的机器学习方法，对2009 - 2017年中国天山造山带发生的30181次1.5 < ML <2.9的地震事件进行了构造地震（TEs）、采石场爆炸（QBs）和诱发地震（IEs）分类。SVM分类器基于训练数据集的判别特征，该训练数据集包括从18 ML≥5.0级地震的余震序列中选择的1,400个te，从事件白天发生百分比大于0.9的地区重复事件中选择的2,881个qb，以及从已知油气田和水库事件中选择的987个ie。判别特征包括1-15 Hz频率范围内观测到的P波和S波信号的谱幅值，经P谱归一化并在整个地震台网上平均，以及事件白天发生的百分比这一可选特征。统计分析表明，SVM分类器对te的准确率为99.81%，对qb的准确率为99.93%，对ie的准确率为99.62%。分类结果表明，37.57%的地震事件为发生在可能矿区的qb地震，以群集的形式出现，白天发生的地震事件百分比大于0.9；50.12%的地震事件为发生在天山造山带各逆冲断层中的te地震；12.31%的地震事件为发生在油气田和水库附近的IEs或浅层构造地震，以群集的形式出现。我们重新评估了该地区的b值，并获得了相对统一的分类te值，其中大多数低于1.0，而在分析中使用所有地震事件时，值的范围很大（0.5-2.7）。
Discriminating between various types of seismic events is of significant scientific and societal importance. We use a machine learning method employing support vector machine (SVM) to classify tectonic earthquakes (TEs), quarry blasts (QBs), and induced earthquakes (IEs) among 30,181 1.5 < ML <2.9 seismic events that occurred in the Tianshan orogenic belt in China from 2009 to 2017. SVM classifiers are derived based on discriminant features of a training data set consisting of 1,400 TEs selected from the aftershock sequences of 18 ML ≥ 5.0 earthquakes, 2,881 QBs from repeating events occurring in those areas with a percentage of event daytime occurrence greater than 0.9, and 987 IEs from events in the known oil/gas fields and water reservoirs. The discriminant features include spectral amplitudes of observed P and S wave signals in a frequency range of 1–15 Hz normalized by the P spectrum and averaged over the entire seismic network, and an optional feature of the percentage of event daytime occurrence. Statistics analyses indicate that the accuracies of the SVM classifiers are 99.81% for TEs, 99.93% for QBs, and 99.62% for IEs. Our classification indicates that 37.57% of the seismic events are QBs occurring in possible mine areas and appearing mostly as clusters with a percentage of event daytime occurrence greater than 0.9, 50.12% are TEs occurring in various thrust faults in the Tianshan orogenic belt, and 12.31% are IEs or shallow tectonic earthquakes occurring mostly as clusters near oil and gas fields and water reservoirs. We reevaluate b values in the region and obtain relatively uniform values for the classified TEs with most of them below 1.0, as opposed to a large range of values (0.5–2.7) when all the seismic events are used in the analysis.