Listening for gas bubbles

What if we could cheaply and efficiently detect a potent new energy source, while also monitoring for environmental safety? Olivier Carrière, a physicist in the Marine Physical Laboratory at the Scripps Institution of Oceanography, and other researchers are using the symphony of sound produced in the ocean to do just that.

When natural gas is released from the seafloor, it produces bubbles; similarly, gas leaking from a pipeline also produces bubbles. Instead of traditional acoustic methods that use active surveys of the ocean floor with sonar or seismic techniques, researchers are developing a revolutionary method that listens for these bubbles passively. If successful, this new advancement could change the way we survey the oceans.

The new passive acoustic techniques allow researchers to listen to the bubbles to identify both gas hydrate deposits — which could be an energy source or a potential hazard — and to keep watch over subsea natural gas pipelines. Read more about this online at http://www.earthmagazine.org/article/listening-gas-bubbles or order the full March issue at EARTH online (http://www.earthmagazine.org).

Make sure to check out the other stories in this month's issue of EARTH: discover whether the Japanese tsunami made their people more vulnerable, find out what mystifying metal was discovered in the Earth's mantle, and see if you have the skills to crack this month's "Where on Earth?"

Provided by American Geological Institute