Sources of Earth’s “hum” pinpointedAugust 9th, 2009 - 12:16 pm ICT by ANI
Washington, August 9 (ANI): A new research has found that the Pacific coasts of North America and Central America are important sources of the Earth’s low-frequency vibration, or “hum”.
Previous studies had found that this hum is excited by infragravity waves, a type of ocean wave that originates in shallow water along coasts, but it was uncertain whether hum is generated primarily by infragravity waves in the deep ocean or along coastlines.
To pinpoint the sources of Earth’s hum, Peter D. Bromirski and Peter Gerstoft from the Scripps Institution of Oceanography, University of California, US, correlated hum intensity data from the EarthScope US Array transportable array with ocean wave height measurements and model simulations.
Their results show that the hum is generated primarily along coasts, with no significant hum generation in the deep ocean.
In particular, they found that the Pacific coasts of North America and Central America are important sources of the hum, and the west coast of Europe is a strong secondary source region, while no significant hum was detected from the Southern Hemisphere during the study period, which is November 2006 to June 2007.
The study is the first to identify these specific source regions for Earth’s hum. (ANI)
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