Parametric Excitation of Internal Gravity Waves in Ocean and Atmosphere as Precursors of Strong Earthquakes and Tsunami

TL;DR

This paper investigates how parametric excitation of internal gravity waves in rotating fluid layers can serve as precursors to earthquakes and tsunamis, highlighting the dual role of dissipative effects and the potential for monitoring these waves.

Contribution

It introduces a new mechanism for IGW generation via parametric resonance in ocean and atmosphere, linking wave behavior to earthquake precursors.

Findings

Dissipative effects can both dampen and induce hydrodynamic instability in IGW.

Parametric resonance can generate detectable IGW precursors during seismic activity.

Localized tornado-like disturbances can also trigger IGW instability.

Abstract

The condition of internal gravity waves (IGW) parametric excitation in the rotating fluid layer heated from above, with the layer vibration along the vertical axis or with periodic modulation in time of the vertical temperature distribution, is obtained. We show the dual role of the molecular dissipative effects that may lead not only to the wave oscillations damping, but also to emergence of hydrodynamic dissipative instability (DI) in some frequency band of IGW. This DI also may take place for the localized in horizontal plane tornado-like disturbances, horizontal scale of which does not exceed the character vertical scale for the fluid layer of the finite depth. Investigated parametric resonance mechanism of IGW generation in ocean and atmosphere during and before earthquakes allows monitoring of such waves (with double period with respect to the period of vibration or temperature gradient modulation) as precursors of these devastating phenomena.