Modelling the electomagnetic field generated by tsunamigenic seabed deformation #

Emiliano Renzi, Marco Mazza

11:30 Tuesday in 4Q07.

Part of the Geophysics and climate session.

Abstract #

We present a novel mathematical model of electromagnetic field variations generated by tsunamigenic disturbance on the seabed. The governing Maxwell equations for the electomagnetic field are paired with a Cauchy-Poisson problem for the transient fluid motion induced by the deformation. Solution is achieved using double Fourier-Laplace transforms in the complex plane. We show that the magnetic field is made by two components. One is proportional to the Airy function and thus is synchronous to the leading tsunami wave. The other component is proportional to the Scorer function and anticipates the arrival of the tsunami. Our results explain the early arrival of the electromagnetic field with respect to the surface gravity wave, which was observed in recent field measurements. Hence our mathematical model provides a rigorous explanation of existing observations and numerical results.