Posted on October 19, 2012

San Luis Obispo County: PG&E Committed to Conducting Seismic Studies in Environmentally Responsible Manner

Diablo Canyon Power Plant

PG&E will take extensive measures to protect marine mammals durring seismic studies in the waters near the Diablo Canyon Power Plant.

PG&E says the seismic testing of earthquake faults near its Diablo Canyon Power Plant will be done safely and in an environmentally responsible manner. The utility continues to work to get the required approvals for this work.

The State of California called on PG&E to conduct advanced seismic research. In response, PG&E developed a comprehensive program that includes the use of onshore 2D and 3D studies, offshore 3D low and high-energy studies as well as the ongoing use of seismic monitoring devices. PG&E will use the data collected from the advanced seismic studies to support its ongoing seismic safety program at Diablo Canyon that continually assesses and validates the seismic design of the facility.

PG&E has made steady progress toward completing these studies since they began in 2010. The onshore work is nearly complete, the majority of the 3D low-energy offshore studies are finished, and the California Coastal Commission has approved the request to install ocean-bottom seismometers to detect seismic activity.

The final 3D high-energy offshore study could begin this November if the necessary permits are granted by local, state and federal bodies.

For more information on PG&E’s seismic research program, please visit

Committed to conduct work safely

To address community and regulator feedback on the final study, PG&E submitted a modified 3D high-energy offshore survey proposal to the California Coastal Commission for consideration during its November meeting.

“PG&E is committed to conducting all of our seismic research safely and in a manner that respects community and environmental values. We appreciate the public and regulator input we have received and continue to work collaboratively to find a balanced solution,” said Jearl Strickland, PG&E’s director of nuclear projects.

The plans, technologies and methods selected to conduct the final high-energy study were formed in consultation with seismic research experts and shared with a state-created Independent Peer Review Panel (IPRP). An appropriate industry-standard research vessel often used for this type of study was selected to conduct the work as it is designed to operate in shallow coastal waters.

PG&E will share information collected from the advanced seismic research with local public and government agencies so they can incorporate it into emergency preparedness plans and ensure the safety of critical infrastructure.  The data also will support a new, federally mandated seismic risk evaluation. All U.S. nuclear power plants were required to conduct such an evaluation by the Nuclear Regulatory Commission after the Fukushima Daiichi power plant tragedy in Japan.

Extensive protective measures

While conducting the survey, PG&E will implement extensive mitigation measures to protect marine mammals. (See graphic below.)

Those measures include the use of specially trained protected-species observers; aerial canvassing of the area before testing begins; warning signals; and the use of an exclusion zone and a safety zone to protect marine animals.

Acoustical and infrared equipment on the research vessel also will be used to monitor for marine life. In addition to the National Marines Fisheries Services, PG&E is working with U.S. Fish and Wildlife Service, California Department of Fish and Game and the U.S. Geological Survey.

Similar seismic research is performed around the world and no adverse, long-term impacts to marine life have been observed. Currently, more than 20 similar surveys are taking place in waters near the coasts of the United States and dozens are happening elsewhere globally.

Recent findings by federal agencies, which regulate the protection of marine mammals, have projected that the environmental impact of the proposed high-energy offshore research might result in a temporary disturbance but would result in no long-term impacts on marine mammals and fish in the survey areas.



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