Abstract
Compared to towed streamers, ocean-bottom seismometers (OBS) obtain both S-wave data and richer wavefield information. In this paper, the induced polarization method is used to conduct wavefield separation on OBS data obtained from the Shenhu area in the South China Sea. A comparison of the changes in P- and S-waves, and a comprehensive analysis of geological factors within the area, enable analysis and description of the occurrence of natural gas hydrate in the study area. Results show an increase in P-wave velocity when natural gas hydrate exists in the formation, whereas the S-wave velocity remains almost constant, as S-waves can only propagate through the rock skeleton. Therefore, the bottom-simulating reflection (BSR) response of the P-wave is better than that of the S-wave in the frequency analysis profile. In a wide-angle section, the refractive wave of the hydrate layer is evident when using P-wave components but identification is difficult with S-wave components. This velocity model illustrates the sensitivity of P- and S-wave components to gas hydrate. The use of this polarization method and results of analysis provide technical and theoretical support for research on hydrate deposits and other geological features in the Shenhu area.
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Acknowledgements
The study is supported by the National Natural Science Foundation of China (Nos. 41304096, 41176077, 412303 18), the National Science and Technology Major Project of China (No. 2016ZX05024-001-002), the National Hightech R&D Program of China (863 Program) (Nos. 2013 AA092501, 2017YFC0307401), and the Fundamental Research Funds for the Central Universities (No. 201762 019).
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Xing, L., Liu, X., Zhang, J. et al. Sensitivity analysis of P-waves and S-waves to gas hydrate in the Shenhu area using OBS. J. Ocean Univ. China 17, 139–146 (2018). https://doi.org/10.1007/s11802-018-3587-6
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DOI: https://doi.org/10.1007/s11802-018-3587-6