Subsurface Imaging With Ocean‐Bottom Distributed Acoustic Sensing and Water Phases Reverberations
Abstract
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.
Additional Information
© 2022. The Authors. This is an open access article under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License, which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made. Issue Online: 19 January 2022. Version of Record online: 19 January 2022. Accepted manuscript online: 10 January 2022. Manuscript accepted: 03 January 2022. Manuscript revised: 06 December 2021. Manuscript received: 20 July 2021. We thank Fujitsu for cooperating with the Earthquake Research Institute (ERI), the University of Tokyo, for the DAS measurement campaigns. All the figures have been plotted with Matplotlib (Hunter, 2007) or the Generic Mapping Tool (Wessel et al., 2019). Some of the data processing steps have been performed using ObsPy (Beyreuther et al., 2010), and Pyrocko (Heimann et al., 2017). We thank Michael Afanasiev and the Mondaic team for their help in setting up the 3D numeric simulations. This project was partly supported by the discretionary budget of the director of ERI. The observations were carried out as part of the Earthquake and Volcano Hazards Observation and Research Program by the Ministry of Education, Culture, Sports, Science, and Technology of Japan. Z.J.S thanks the Air Force Research Laboratory through project FA9453-21-2-0018. L.V was supported by NSF award EAR2022716, and J.C.C. was supported by NSF CAREER award 1848166 and the Gordon and Betty Moore Foundation. The authors wish to thank the editor Daoyuan Sun, and two anonymous referees for their reviews that helped to improve the quality of the paper and the interpretation of the results. The authors declare no conflicts of interest relevant to this study. Data Availability Statement. All the data necessary to reproduce the results presented in the paper (e.g., earthquakes #1 & #2) are open access and available at https://doi.org/10.5281/zenodo.5110823. The Gridded Slant-Stack code is available for download on GitHub (https://github.com/zackspica/Gridded-SlantStack) with https://doi.org/10.5281/zenodo.5608598.Attached Files
Supplemental Material - 2021gl095287-sup-0001-supporting_information_si-s01.pdf
Supplemental Material - 2021gl095287-sup-0002-movie_si-s01.mp4
Supplemental Material - 2021gl095287-sup-0003-movie_si-s02.mp4
Supplemental Material - 2021gl095287-sup-0004-movie_si-s03.mp4
Supplemental Material - 2021gl095287-sup-0005-movie_si-s04.mp4
Supplemental Material - 2021gl095287-sup-0006-movie_si-s05.mp4
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Additional details
- Eprint ID
- 113024
- Resolver ID
- CaltechAUTHORS:20220120-890578000
- FA9453-21-2-0018
- Air Force Research Laboratory
- EAR-2022716
- NSF
- EAR-1848166
- NSF
- Gordon and Betty Moore Foundation
- Created
-
2022-01-21Created from EPrint's datestamp field
- Updated
-
2022-01-21Created from EPrint's last_modified field
- Caltech groups
- Seismological Laboratory