Subsurface Imaging with Ocean‐Bottom Distributed Acoustic Sensing and Water Phases Reverberations
Subsurface Imaging with Ocean‐Bottom Distributed Acoustic Sensing and Water Phases Reverberations
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DOI：
10.1029/2021gl095287
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发表时间：
2022-01
影响因子：
5.2
通讯作者：
Z. Spica;J. Castellanos;L. Viens;Kiwamu Nishida;T. Akuhara;M. Shinohara;Tomoaki Yamada
中科院分区：
文献类型：
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作者：
Z. Spica;J. Castellanos;L. Viens;Kiwamu Nishida;T. Akuhara;M. Shinohara;Tomoaki Yamada
海底记录的地震波由复杂的多次波到达组成。在这里，分布式声学传感（DAS）观测沿着电缆位于三陆海岸，日本，表明当地的地震波场是特别丰富的Scholte波。我们引入了一个处理管道，从DAS记录中提取这些表面波。然后，我们沿电缆的一段沿着反演数百条频散曲线，以形成浅层高分辨率剪切波速度模型。此外，我们通过一系列二维和三维全波场数值模拟，重点研究了Scholte波的可能产生机制。我们表明，水相混响极大地有助于生成Scholte波在海底。这项研究表明，DAS的潜力，以观察和更好地了解一个鲜为人知的海浪现象和图像的近海浅层地震结构与前所未有的空间分辨率。
Seismic waves from earthquakes recorded on the seafloor are composed of complex multiple arrivals. Here, distributed acoustic sensing (DAS) observations along a cable located offshore the Sanriku Coast, Japan, show that the local earthquake wavefield is particularly rich in Scholte waves. We introduce a processing pipeline to extract these surface waves from DAS records. We then invert hundreds of dispersion curves along a section of the cable to form a shallow high‐resolution shear‐wave velocity model. Moreover, we focus on the possible generation mechanisms of Scholte waves through a series of 2D and 3D full‐wavefield numerical simulations. We show that water phase reverberations greatly contribute to the generation of Scholte waves on the ocean floor. This study demonstrates the potential of DAS to observe and better understand a poorly known marine wave phenomenon and image the offshore shallow seismic structure with an unprecedented spatial resolution.