Southern California Edison, Scripps Institution of Oceanography to Collaborate on Offshore Seismic Research Project at San Onofre

Scripps Professor Neal Driscoll, lead scientist on the new mapping project. Photo by Marc Tule

Southern California Edison (SCE) and Scripps Institution of Oceanography at UC San Diego will collaborate on a project to gather seismic data off the coast of the San Onofre Nuclear Generating Station (SONGS). The work, part of SCE's seismic research projects for SONGS Units 2 and 3, will involve state-of-the art data-gathering and analysis technologies and will begin later this year and continue through 2013.

Scripps scientists will lead the project, which will include collecting and processing data from 2-D and 3-D multichannel seismic reflection and refraction off San Onofre State Beach. The raw and processed survey data will be open-source and available to other experts to view and use in further studies. This data will also be made available to the general public. Offshore seismic research is conducted with specially equipped boats that tow cables, or streamers, with underwater microphones at regular intervals. Two-dimensional seismic surveys usually have one streamer; three-dimensional surveys have four or more.

"Our No. 1 priority is safety, and seismic safety plays an important role in our operations at the plant," said Caroline McAndrews, SCE director of nuclear strategic projects. "Having Scripps take the lead on this important project will provide us with objective and world-class expertise in geophysics, and increase our understanding of SONGS' seismic setting. This knowledge is key to ensuring the continued safe operation of SONGS."

Besides evaluating the existing and potential faults in the area, the seismic reflection and refraction surveys will image the offshore structures at an unprecedented resolution, and will allow scientists to test the alternative hypotheses for the tectonic deformation observed off San Onofre. In addition, the geophysical surveys will reveal vertical motions of the crust through time, associated with margin reorganization.

Both units of the plant are currently safely shut down for inspections, analysis and tests. Unit 2 was taken out of service Jan. 9 for a planned outage. Unit 3 was safely taken off line Jan. 31 after station operators detected a leak in one of the unit's steam generator tubes.