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.
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.