July 15, 2009

Satellites Can Detect Tsunamis

U.S. government researchers announced Wednesday that satellites can spot the leading edge of a Tsunami by detecting giant waves and getting people out of their way.

The researchers looked at satellite images in the Indian Ocean as the December 2004 tsunami hit Thailand, Sri Lanka and other places.  They found patterns in the water that shows evidence of the big wave.

"We've found that roughness of the surface water provides a good measure of the true strength of the tsunami along its entire leading edge," Oleg Godin of the National Oceanic and Atmospheric Administration in Boulder, Colorado, said in a statement.

"This is the first time that we can see tsunami propagation in this way across the open ocean."

An earthquake in Indonesia triggered the 2004 tsunami, which killed over 228,000 people.

Since then, governments have rushed to complete an early warning system of mid-ocean buoys that would detect waves as they pass by.  However, a system like this is imperfect and might miss areas, especially as the buoys cannot be placed everywhere.

Tsunamis can only normally be seen when they enter shallow water.  The wave in the depths of the ocean can barely be seen, although satellites can detect this tiny movement.

However, the satellites that can detect this do not cover all the world's seas.

Godin's team found that tsunamis crossing the open ocean stir up and darken the surface waters along the leading edge of the wave.  The team reported in the journal Natural Hazards and Earth System Sciences that many ordinary satellites can detect the dark pattern.


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