Seabed cable signals sense tsunamis

Nair and his colleagues used computer models to estimate the size of an electric field created by the force of the 2004 Indian Ocean tsunami as it travelled over major submarine cables.

‘We estimate that the 2004 tsunami induced voltages of about 500mV in the cables,’ said Nair. ‘This is very small but still large enough to be distinguished from background noise on a magnetically quiet day.

‘By monitoring voltages across this network of ocean cables, we may be able to enhance the current tsunami warning system.’

However, he warned that much research is still needed to effectively isolate the tsunami signals from other sources, such as Earth’s upper atmosphere, or ionosphere, whose signals can reach 100mV.

Tsunamis are created by a large displacement of water resulting from earthquakes, landslides, volcanic eruptions and even meteors hitting the ocean. Vessels far out at sea may not notice the waves passing underneath at the speed of a jetliner, because the wave heights are very small in the deep ocean. This makes their detection and monitoring a challenge.