Influence of a Subducted Oceanic Ridge on the Distribution of Shallow VLFEs in the Nankai Trough as Revealed by Moment Tensor Inversion and Cluster Analysis
Influence of a Subducted Oceanic Ridge on the Distribution of Shallow VLFEs in the Nankai Trough as Revealed by Moment Tensor Inversion and Cluster Analysis
复制标题
矩张量反演和聚类分析揭示俯冲洋脊对南开海槽浅层VLFE分布的影响
DOI：
10.1029/2020gl087244
复制
发表时间：
2020
影响因子：
5.2
通讯作者：
Ide S.
中科院分区：
文献类型：
--
作者：
Toh A.;Chen W. J.;Takeuchi N.;Dreger D. S.;Chi W. C.;Ide S.
南开海槽东部是一个独特的地点，附近的宽带海底地震仪记录了许多浅层极低频地震（sVLFEs）。在这里，我们根据记录的低频（<0.07 Hz）分量估计了svlfe的位置和地震矩张量（MTs）。尽管一些svfes表现出长持续时间的信号（100 ~ 100秒），表明源的复杂性，但MT反演仅限于脉冲和短持续时间（20 ~ 30秒）的事件。然而，聚类分析证实，脉冲svlfe的mt合理地代表了包括许多持续时间较长的事件在内的事件组的整体变形。MTs的分布表明，在该地区，与slv相关的变形受俯冲洋脊的影响，在应变积累/释放模式下产生沿槽的变化，并可能控制海啸发生的空间格局。
The eastern Nankai Trough is a unique site where many shallow, very low frequency earthquakes (sVLFEs) are recorded by nearby broadband ocean bottom seismometers. Here, we estimated the locations and seismic moment tensors (MTs) of sVLFEs based on the low‐frequency (<0.07 Hz) components of the records. Although some sVLFEs exhibited long‐duration signals (>100 s), indicating a degree of source complexity, the MT inversions were limited to events with impulsive and short durations (20–30 s). Nevertheless, cluster analysis confirmed that the MTs of impulsive sVLFEs reasonably represented the overall deformation for an event group including many longer‐duration events. The distribution of MTs indicates that deformations associated with sVLFEs are influenced by a subducted oceanic ridge in this region, which produces an along‐the‐trough variation in a strain accumulation/release pattern and probably controls the spatial patterns of tsunami generation.