Long-range atmospheric infrasound propagation from subsurface sources
Long-range atmospheric infrasound propagation from subsurface sources
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DOI：
10.1121/10.0000792
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发表时间：
2020-02-01
影响因子：
2.4
通讯作者：
Evers, Laslo G.
中科院分区：
文献类型：
--
作者：
Averbuch, Gil;Assink, Jelle D.;Evers, Laslo G.
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。类似地，这些界面被认为是次声传播的刚性表面。这意味着地震波或声波不会从地下震源传播到大气中，反之亦然。然而，已经观察到由地下声源产生的次声。在这项工作中，将介绍水下和地下次声传播的地震声学模拟。采用快速场程序(FFP)模拟了震源参数和介质参数变化时固体地球、海洋和大气之间的地声耦合。FFP模型可以在频率-波数空间中详细分析地震-声学耦合机制。对耦合机制的深入分析表明，逝去波耦合和泄漏表面波是长距离次声传播的主要能量贡献者。此外，还发现震源深度影响对流层和平流层位相的相对幅度，这为今后的震源深度估计奠定了基础。
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.