Tiny tremors can track extreme storms in a warming planet

April 18th, 2008 - 12:08 pm ICT by admin  

Washington, April 18 (IANS) Data from faint earth tremors caused by wind-driven ocean waves - often dismissed as “background noise” at seismographic stations - suggest extreme ocean storms have become more frequent over the past three decades, according to a study. The International Panel on Climate Change (IPCC) and other prominent researchers have predicted that stronger and more frequent storms may occur as a result of global warming trends.

The tiny tremors, or microseisms, offer a new way to discover whether these predictions are already coming true, said Richard Aster, of the New Mexico Institute of Mining and Technology.

Unceasing as the ocean waves that trigger them, the microseisms show up as five- to 30-second oscillations of the earth’s surface at seismographic stations around the world.

Even seismic monitoring stations “in the middle of a continent are sensitive to the waves crashing all around the continent”, Aster said.

As storm winds drive ocean waves higher, the microseism signals increase their amplitude as well, offering a unique way to track storm intensities across seasons, over time, and at different geographical locations.

For instance, Aster and colleagues recently published analysis in the journal Seismological Research Letters showing that microseism data could be used to detect and quantify wave activity from multi-year events such as the El Ni

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