Can we improve the accuracy of Tsunami warning systems – potentially saving lives – with science?
Earthquake-generated tsunamis, caused by the vertical displacement of water above ruptured crust, are among the major natural catastrophes of the recent past. Japan’s Tohoku-Oki earthquake of March 2011 and the Boxing Day tsunami of 2004 in the Indian Ocean caused enormous devastation and between them cost over a quarter of a million lives. Now a study from the GFZ German Research Centre for Geosciences demonstrates a new method of increasing the accuracy of warning systems.
Tsunami Warning Systems
Tsunamis are a major threat to human populations. The earthquakes which generate them occur at subduction zones, where one of the Earth’s tectonic plates is subducted beneath another. The nature of plate tectonics dictates that many of these subduction zones are very close to coasts – often densely inhabited. A tsunami spreads out from the epicentre of an earthquake and, while it may take many hours to cross an ocean, it will crash upon a neighbouring shore in just a few minutes.
Given the location of the world’s subduction zones, areas around the Pacific, in particular, are highly vulnerable: not just Japan, but areas such as the Philippines, the Pacific coastal strip of South America and many communities in the states of Washington and Oregon are among those at risk. In the light of this, and of the unpredictability of a major earthquake at any given location, it’s vital that as much warning is given as possible to allow for evacuation.
Current tsunami warning systems rely on a combination of seismic data and wave information relayed by satellite from pressure-sensitive anchored buoys known as DART buoys. Seismic information comes from the triggering earthquake and, because seismic waves travel much faster than tsunami waves, they are often the first indication that a tsunami may have been generated.