EGU21-8284, updated on 04 Mar 2021
https://doi.org/10.5194/egusphere-egu21-8284
EGU General Assembly 2021
© Author(s) 2021. This work is distributed under
the Creative Commons Attribution 4.0 License.

A variety of surface waves in ocean-bottom DAS records

Zack Spica1, Loïc Viens, Jorge Castillo Castellanos2, Takeshi Akuhara3, Kiwamu Nishida3, Masanao Shinohara3, and Tomoaki Yamada4
Zack Spica et al.
  • 1University of Michigan, United States of America (zspica@umich.edu)
  • 2California Technological Institute
  • 3Earthquake Research Institute, University of Tokyo
  • 4Japan Meteorological Agency

Distributed acoustic sensing (DAS) can transform existing telecommunication fiber-optic cables into arrays of thousands of sensors, enabling meter-scale recordings over tens of kilometers. Recently, DAS has demonstrated its utility for many seismological applications onshore. However, the use of offshore cables for seismic exploration and monitoring is still in its infancy.
In this work, we introduce some new results and observations obtained from a fiber-optic cable offshore the coast of Sanriku, Japan. In particular, we focus on surface wave retrieved from various signals and show that ocean-bottom DAS can be used to extract dispersion curves (DC) over a wide range of frequencies. We show that multi-mode DC can be easily extracted from ambient seismo-acoustic noise cross-correlation functions or F-K analysis. Moderate magnitude earthquakes also contain multiple surface-wave packets that are buried within their coda. Fully-coupled 3-D numerical simulations suggest that these low-amplitude signals originate from the continuous reverberations of the acoustic waves in the ocean layer. 

How to cite: Spica, Z., Viens, L., Castillo Castellanos, J., Akuhara, T., Nishida, K., Shinohara, M., and Yamada, T.: A variety of surface waves in ocean-bottom DAS records, EGU General Assembly 2021, online, 19–30 Apr 2021, EGU21-8284, https://doi.org/10.5194/egusphere-egu21-8284, 2021.

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