Averbuch Gil, Assink Jelle D, Evers Läslo G
Department of Geoscience and Engineering, Faculty of Civil Engineering and Geosciences, Delft University of Technology, 1 Stevinweg Street, Delft, The Netherlands.
R&D Department of Seismology and Acoustics, Royal Netherlands Meteorological Institute, P.O. Box 201, 3730 AE De Bilt, The Netherlands.
J Acoust Soc Am. 2020 Feb;147(2):1264. doi: 10.1121/10.0000792.
In seismology and ocean acoustics, the interface with the atmosphere is typically represented as a free surface. Similarly, these interfaces are considered as a rigid surface for infrasound propagation. This implies that seismic or acoustic waves are not transmitted into the atmosphere from subsurface sources, and vice versa. Nevertheless, infrasound generated by subsurface sources has been observed. In this work, seismo-acoustic modeling of infrasound propagation from underwater and underground sources will be presented. The fast field program (FFP) is used to model the seismo-acoustic coupling between the solid earth, the ocean, and the atmosphere under the variation of source and media parameters. The FFP model allows for a detailed analysis of the seismo-acoustic coupling mechanisms in frequency-wavenumber space. A thorough analysis of the coupling mechanisms reveals that evanescent wave coupling and leaky surface waves are the main energy contributors to long-range infrasound propagation. Moreover, it is found that source depth affects the relative amplitude of the tropospheric and stratospheric phases, which allows for source depth estimation in the future.
在地震学和海洋声学中，与大气的界面通常被表示为自由表面。同样，这些界面在次声传播中被视为刚性表面。这意味着地震波或声波不会从地下源传输到大气中，反之亦然。然而，已经观测到地下源产生的次声。在这项工作中，将介绍水下和地下源次声传播的地震声学建模。快速场程序（FFP）用于在源和介质参数变化的情况下，对固体地球、海洋和大气之间的地震声学耦合进行建模。FFP模型允许在频率 - 波数空间中对地震声学耦合机制进行详细分析。对耦合机制的深入分析表明，倏逝波耦合和泄漏表面波是远距离次声传播的主要能量贡献者。此外，发现源深度会影响对流层和平流层相位的相对振幅，这使得未来能够估计源深度。
