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Debate seismic tests near Calif. nuke plant

SAN FRANCISCO -- Plans to use an array of powerful air cannons in an undersea seismic study near a central California nuclear power plant have federal and state officials juggling concerns over marine life with public safety.

Pacific Gas & Electric Co. wants to use the big air guns to emit strong sound waves into a large, near-shore area that includes parts of marine reserves to make three-dimensional maps of fault zones, some of which were discovered in 2008, near its Diablo Canyon nuclear power plant.

But a state study found the project is likely to have "unavoidable adverse effects" on marine life and the environment. Biologists, environmental groups and fishermen have opposed using the high-energy guns, saying the blasts have the potential to harm endangered whales, California sea otters and other creatures frequenting these waters.

The $64 million, ratepayer-funded effort to understand seismic threats to the plant has intensified since the disastrous 2011 Tohoku quake and tsunami, which disabled reactors at Japan's Fukushima Dai-ichi nuclear power plant. Quake experts were surprised by the 9.0-magnitude quake on a fault they did not believe would produce a quake stronger than 8.0.

PG&E wants to know whether the newly discovered faults near San Luis Obispo are connected to existing ones that have already been studied.

If the project gains approval from myriad agencies, 18 air guns and sensors would be dragged through a region that includes two state marine protected areas and is adjacent to the Monterey Bay National Marine Sanctuary. Dozens of endangered and threatened species use these waters.


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