Can undersea voltage measurements detect tsunamis?

Abstract

The movement of electrically conducting ocean water in the ambient geomagnetic eld induces secondary electric and magnetic elds in the oceans. Ocean water transport is now routinely inferred from undersea cable voltage data. We try to answer the question whether the method could also be useful to detect tsunami. A barotropic shallow water model along with a three-dimensional electromagnetic induction code was used to predict the electric elds induced by the Indian Ocean Tsunami occurred on December 26, 2004. We show that the ocean ow related to the Indian Ocean Tsunami must have induced electric voltages of the order of ±500 mV across the existing submarine cables in the Indian Ocean. The electric elds induced by the Tsunami ow have strength within the range of ±10 mV/km, with enhancements along the main ow region and near the coasts and islands. Thus, making use of the in-service or retired submarine cables to measure the electric potential across oceans, it may be possible to detect water movement related to tsunami.

Space–time behaviour of magnetic anomalies induced by tsunami waves in open ocean

“…From the World Magnetic Model 2005-2010, the vertical magnetic intensity is around 20 000 nT at this site. The peak values of the horizontal magnetic field shown in figure 7 agree well with the values predicted by Tyler [30] and Manoj et al [39] at sea-surface level when the ratio F (z) /F (x) is taken into account.…”

“…The magnetic signal due to the Sumatra tsunami might reach 3 nT for the vertical magnetic component at sea level, as estimated using a simple formula by Tyler [30]. Using the wave field calculated by shallow water equations, Manoj et al [39] predicted the magnetic strength to be a similar level as that of Tyler [30]. From the World Magnetic Model 2005-2010, the vertical magnetic intensity is around 20 000 nT at this site.…”

Observation of Magnetic Fields Generated by Tsunamis

“…The characteristics of the observed tsunami signals also may be used to search for tsunami signals in historic magnetic records. A recent study [Manoj et al, 2010] found that tsunamis could also induce observable electric potentials in deepsea cables that might be used to detect the tsunami flows. However, the disturbances from the Earth's magnetosphere could restrict the practical utility of tsunami electromagnetic monitoring to periods of low solar activity.…”

Three‐dimensional simulation of the electromagnetic fields induced by the 2011 Tohoku tsunami

“…Manoj et al . [] studied the possibility of detecting electric and magnetic fields induced by the 2004 Sumatra tsunami by rigorous implementation of Maxwell's equations in spherical geometry.…”