Undersea volcano: Heard but not seen

Seismologists in Oregon have been eavesdropping on the rumblings of a mysterious submarine volcano since May 1998, but they haven’t been able to locate the loudmouth.

Volcano appears to lie in a 1,500-square-km region (yellow area).

The scientists, from the National Oceanic and Atmospheric Administration (NOAA), use a network of underwater microphones, or hydrophones, to listen to the ocean.