Global seismic event detection using a matched filter on long‐period seismograms
Global seismic event detection using a matched filter on long‐period seismograms
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DOI：
10.1029/94jb00498
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发表时间：
1994-07
影响因子：
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通讯作者：
P. Shearer
中科院分区：
文献类型：
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作者：
P. Shearer
将长周期地震图叠加得到的图像作为经验匹配滤波器用于地震探测和定位。国际加速度计部署（IDA）网络的15至20个台站在很长周期（T≥60秒）记录的564个事件（mb≥6）的记录使用强调表面波到达的方法进行叠加。该时间与距离图像的前3小时用于构建匹配的过滤器，以便连续应用于IDA数据。该滤波器的输出包含空间和时间峰值，这些峰值定义了可能地震事件的位置和起源时间。该技术对1981年至1991年11年的IDA数据的实现确定了4061个事件。这包括65%的mb≥5.5的已编目事件。相对于其表面波震级显得异常强烈的地震主要位于海洋转换断层上，可能代表异常缓慢的破裂。该方法成功地探测到墨西哥南部埃尔奇洪火山的两次喷发，从火山喷发期间辐射的异常低频能量。此外，还检测到32次地震，这些地震没有列入标准的全球地震目录。这些事件似乎约为Ms = 5，主要位于南部海洋，那里有高频网络覆盖范围的空白。虽然这些地震可能是“缓慢的”，因为它们大多发生在海洋转换断层上，但它们并不是“无声的”，因为它们也可以在更高频率的数据中观察到。
An image derived by stacking long-period seismograms is used as an empirical matched filter to detect and locate earthquakes. Records from 564 events (mb ≥ 6) recorded at very long periods (T ≥ 60 s) by the 15 to 20 stations of the International Deployment of Accelerometers (IDA) network are stacked using a method that emphasizes the surface wave arrivals. The first 3 hours of this time versus range image are used to construct a matched filter for continuous application to the IDA data. The output of this filter contains spatial and temporal peaks that define the location and origin time of probable seismic events. Implementation of this technique to 11 years of IDA data from 1981 to 1991 identifies 4061 events. These include 65% of cataloged events of mb ≥ 5.5. Earthquakes which appear anomalously strong relative to their surface wave magnitudes are mainly located on oceanic transform faults and probably represent unusually slow ruptures. The method successfully detects two eruptions of the El Chichon volcano in southern Mexico, from the anomalous low-frequency energy radiated during the eruptions. In addition, 32 earthquakes are detected which are not in the standard global catalogs. These events appear to be about Ms = 5 and are mainly located in the southern oceans, where there are gaps in the coverage of the high-frequency networks. Although these earthquakes are probably “slow” since they occur mostly on oceanic transform faults, they are not “silent” as they also can be observed in higher-frequency data.