Environmentalists oppose PG&E plans for undersea air blasts

http://www.latimes.com/news/local/la-me-sonic-20120929,0,7977891.story

Over objections of Central Coast residents and environmental groups, Pacific Gas & Electric plans to map earthquake fault zones near its Diablo Canyon nuclear plant by blasting high-decibel air cannons under the surface of the ocean.

PG&E's plan calls for towing a quarter-mile-wide array of underwater "air cannons" that emit 250-decibel blasts into the ocean every 15 seconds for 12 straight days. The sonic reflections would be picked up by underwater receivers and analyzed to provide detailed 3-D images of the geometry, relationships and ground motions of several fault zones near the Diablo facility, which generates enough energy to meet the needs of more than 3 million Northern and Central Californians.

Opponents say the method threatens sea creatures from Central Coast rockfish to whales, and they dispute PG&E's claims that there are no alternative, less harmful technologies available for the job.