Modeling of the hydroacoustic signal and tsunami wave generated by seafloor motion including a porous seabed

Abstract

[1] Within the framework of a 2-D compressible tsunami generation model with a flat porous seabed, acoustic waves are generated and travel outward from the source area. The effects of the porous seabed during tsunami generation and propagation processes include wave amplitude attenuation and low-pass filtering of both the hydroacoustic signal and tsunami wave. The period of the acoustic wave generated by the seafloor motion depends on water depth over the source area and is given by four times the period of time required for sound to travel from the seabed to the surface. These waves carry information about seafloor motion. The semianalytical solution of the 2-D compressible water layer model overlying a porous seabed is presented and discussed. Furthermore, to include the effects generated by the coupling between compressible porous sedimentary and water layers, a simplified two-layer model with the sediment modeled as a compressible viscous fluid is presented.Citation: Chierici, F., L. Pignagnoli, and D. Embriaco (2010), Modeling of the hydroacoustic signal and tsunami wave generated by seafloor motion including a porous seabed,

Pressure field induced in the water column by acoustic‐gravity waves generated from sea bottom motion

“…Notwithstanding, it is known that properties of AGWs depend on rupture model parameters such as the vertical and lateral extent and duration of bottom motion [Yamamoto, 1982;Nosov, 1999;Chierici et al, 2010;Stiassnie, 2010;Hendin and Stiassnie, 2013]. Current AGW models consider simple geometries and displacements of bottom motions.…”

“…Current AGW models consider simple geometries and displacements of bottom motions. Example of these motions include rectangular disturbances with constant [Nosov, 1999;Chierici et al, 2010;Stiassnie, 2010;Hendin and Stiassnie, 2013] or variable velocities [Yamamoto, 1982;Nosov and Kolesov, 2007;Abdolali et al, 2015a] in the two-dimensional problem, or circular disturbances with constant velocities in the three-dimensional case [Hendin and Stiassnie, 2013].…”

“…If the compressibility of the ocean is considered, a disturbance at the ocean floor may generate Acoustic-Gravity Waves (AGWs), progressive compression-type waves that travel at near the speed of sound in water. Recent studies indicate that as AGWs travel they leave measurable bottom pressure signatures that can act as tsunami precursors [Stiassnie, 2010;Chierici et al, 2010;Kadri and Stiassnie, 2012;Hendin and Stiassnie, 2013;Cecioni et al, 2014;Abdolali et al, 2015a]. In this regard, it is anticipated that such utilization of AGWs would enhance current early tsunami detection systems.…”

“…Yamamoto [1982], Nosov [1999], Chierici et al [2010], Stiassnie [2010], and Hendin and Stiassnie [2013] show theoretically how an ocean bottom uplift can simultaneously generate a tsunami and AGWs. They demonstrate that the magnitudes of a tsunami and AGWs depend on the same parameters such as the water depth, vertical displacement, and duration and length of the bottom uplift.…”

Large-scale numerical modeling of hydro-acoustic waves generated by tsunamigenic earthquakes

“…Moreover, the hydro-acoustic wave signals contain significant information on the tsunamigenic source Chierici et al, 2010). Therefore the detection and the complete modeling of hydroacoustic waves (speed around 1500 m s −1 ), together with measurements of seismic waves (speed around 5000 m s −1 ), could in principle dramatically improve the effectiveness of tsunami early warning systems.…”