Faint earth tremors can track extreme storms

April 18th, 2008 - 2:54 pm ICT by admin  

Washington, April 18 (ANI): A new research has suggested that data from faint earth tremors caused by wind-driven ocean waves can track extreme storms.

Often dismissed as background noise at seismographic stations around the world, the tiny tremors suggest extreme ocean storms have become more frequent over the past three decades, according to the research presented at the annual meeting of the Seismological Society of America.

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, a geophysics professor at 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 Earths 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, said Aster.

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 example, Aster and colleagues recently showed that microseism data collected around the Pacific Basin and throughout the world could be used to detect and quantify wave activity from multi-year events such as the El Nino and La Nina ocean disruptions.

The findings spurred them to look for a microseism signal that would reveal whether extreme storms were becoming more common in a warming world.

In fact, they saw that among the worldwide microseism data collected from 1972 to 2008, in 22 of the 22 stations included in the study, the number of extreme storm events had increased over time.

According to Aster, while the work on evaluating changes in extreme storms is still very much in its early stages, the study will offer a much more global look at the effects of climate change on extreme storms and the wind-driven waves that they produce. (ANI)

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