Modal propagation of ocean acoustic waves generated by earthquakes
| Autor: | Claude Guennou, Jean-Yves Royer, Jean Lecoulant, Laurent Guillon |
|---|---|
| Přispěvatelé: | Laboratoire Géosciences Océan (LGO), Institut Français de Recherche pour l'Exploitation de la Mer - Brest (IFREMER Centre de Bretagne), Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Institut Français de Recherche pour l'Exploitation de la Mer (IFREMER)-Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche de l'Ecole Navale (IRENAV), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Arts et Métiers Sciences et Technologies, HESAM Université (HESAM)-HESAM Université (HESAM), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Universitaire Européen de la Mer (IUEM), Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Brest (UBO)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS) |
| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
[SDU.STU.GP]Sciences of the Universe [physics]/Earth Sciences/Geophysics [physics.geo-ph]
spectral element modeling Magnitude (mathematics) 010502 geochemistry & geophysics 01 natural sciences 010305 fluids & plasmas Physics::Geophysics symbols.namesake 0103 physical sciences Abyssal T-waves Rayleigh scattering 0105 earth and related environmental sciences geography geography.geographical_feature_category Hydrophone Abyssal plain Resonance Crust Acoustic wave SN-waves Seafloor spreading PN-waves Rayleigh modes symbols Seismology Geology |
| Zdroj: | OCEANS 2019-Marseille OCEANS 2019 MTS/IEEE OCEANS 2019 MTS/IEEE, Jun 2019, Marseille, France. ⟨10.1109/OCEANSE.2019.8867377⟩ |
| Popis: | International audience; The generation of low-frequency (≤ 40 Hz) acoustic waves (T-waves) by undersea earthquakes below a flat abyssal plain is not yet fully understood. To model the generation and propagation of PN-waves (horizontally in the crust and vertically in the ocean) and of T-waves over a rough sea bottom, we use a 2D spectral finite-element code (SPECFEM2D). The model includes a solid layer (Earth crust) overlain by a fluid ocean, and separated by a sinusoidal crust/water interface (seafloor roughness). Synthetic T-waves propagate as Rayleigh modes with their expected vertical and long-range horizontal propagation. In the simulated PN-wave spectrum, resonance peaks appear at frequencies predicted by the analytical solution for Rayleigh modes. The same peaks are observed in actual T-wave records from an antenna of two hydrophones at different, generated by a large magnitude earthquake 987 km away. The T-waves spectrum from the shallowest hydrophone shows an energy gap in the 1-4 Hz frequency range that can be explained by modal propagation. The resonance peaks in the observed PN-wave spectrum are also well predicted by the analytical solution. |
| Databáze: | OpenAIRE |
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