Threat of California coastal seismic testing

Posted by Christine, April 18, 2012

The San Luis Obispo Tribune published opinions on opposite sides of the proposed seismic testing Pacific Gas & Electric wants to do to determine risks associated with earthquakes to its Diablo Canyon Nuclear Plant. Here they are:


There is a very serious threat to our fisheries and all marine mammal life looming in the very near future courtesy of PG&E.

In order to renew its operating license for Diablo Canyon nuclear power plant, PG&E is required to perform a seismic study off the Central Coast. According to the Environmental Impact Report dated March 16, the seismic study area mapped out is from above Cambria to below Guadalupe. In fishing terms, from San Simeon to Point Sal.

The basic facts of the seismic survey are: PG&E plans to run a ship that to my understanding is more than 200 feet long towing six cables. These cables have air guns attached that will blast every 30 seconds. This seismic study is to last 82 days running seven days a week, 24 hours a day, not taking into account bad weather and marine mammal sightings. It is a federal law that marine mammals may not be disturbed or harmed in any way. A study of this magnitude has never been done before.

The commercial fishermen of Morro Bay and Port San Luis have a list of concerns:

1. The survey will be conducted in Marine Protected Areas and Rock Cod Recovery Zones. These are essential fish habitat where no commercial fishing is allowed by law. Yet PG&E plans to test in these areas.

2. The environmental impact report is based on 1980s low-energy seismic testing done for oil surveys. In the ’80s, marine life was affected for three years. This 1980s test was done at a much lower decibel level with only one cable. One fisherman, a commercial diver at the time, recalls being forced out of the water 10 miles away from the sound. (Sound travels 10 times further underwater.)

3. The environmental impact report seems to be flawed, using incorrect blocks or landing areas for commercial fishing as well as dated economic data for our commercial fishing seasons and landings.

4. The environmental impact report states that the air guns should only create a temporary hearing loss to fish and marine mammals. We feel this is incorrect. Fish have ear bones that can be easily shattered, and this would devastate shallow area rock fish. Recovery time was based on East Coast species, not West Coast species.

5. Larvae and fish eggs will be severely damaged or destroyed by this study.

If this study goes on as planned, there will be serious damage to our local economy from money lost from the study’s effects on commercial fishing, sport fishing and whale and marine mammal watching. PG&E seems to be unresponsive to negotiations in regards to mitigation of damages.

Please, if you care about our coastal environment, our marine mammals and our coastal economy, attend the public hearing Thursday. Please let our Board of Supervisors and other elected officials know that this seismic study is not OK.

Lori French is a longtime commercial fisherman’s wife, Morro Bay Chamber of Commerce director, Morro Bay Harbor Festival director, Central Coast Women for Fisheries past director, Morro Bay Commercial Fisherman’s Organization past director and the Founder of The Faces of California Fishing Education and Outreach Program. She wrote this on behalf of the commercial fishermen of Morro Bay and Port San Luis.

For as long as it has existed, the issues surrounding Diablo Canyon nuclear power plant have been complex and the stakes have been high. The production of huge quantities of electrical power, with its enormous economic impact, brings with it difficult discussions on issues such as the handling of high-level nuclear waste and the safety of plant operations in a seismically-active region. We have long wrestled with the costs, benefits and risks of this powerful facility.

In the devastating aftermath of the Fukushima earthquake and tsunami, our concerns about risk have been raised further. The unthinkable did occur in Japan: An earthquake and tsunami much larger than expected caused a nuclear disaster that will not be resolved in the foreseeable future. That event has reasonably caused us to re-examine the risks of nuclear power and its vulnerability to natural disaster.

Assessments of earthquake threats to Diablo Canyon were under way well before the Fukushima event. Pacific Gas and Electric has studied the earthquake potential near Diablo Canyon since the 1980s, having discovered the Hosgri fault 3 miles offshore of the plant.

In 2006, state Sen. Sam Blakeslee sponsored legislation (AB 1632) to mandate review of the seismic hazard posed to both the San Onofre and Diablo Canyon nuclear plants. In 2008, the California Energy Commission issued recommendations for further intensive geophysical surveys in their AB 1632 report. Also in 2008, a fault was discovered to run along the shoreline near the Diablo Canyon plant, and the need for further study of earthquake risks was clear.

Full assessment of the earthquake hazard affecting Diablo Canyon requires a variety of geophysical studies, including a high-resolution, three-dimensional seismic reflection survey, conducted offshore both north and south of the plant. This survey will use reflected sound waves to produce 3-D images of subsurface geologic structures, most importantly, the location, size and orientation of faults capable of generating significant earthquakes.

The main sound sources for this imaging effort are “air guns” towed in the water behind the survey ship. The release of high-energy compressed air from these devices creates waves that reflect from geologic formations below the sea bottom.

It’s well-understood that the noise of these air guns will impact marine life and the activities of our commercial fishing industry. These impacts, and ways to mitigate them, have been studied in a draft Environmental Impact Report, prepared as part of the permitting process required of PG&E. Because the proposed survey covers a large area — more than 500 square miles of ocean surface — some of the impacts are considered significant.

Discussion is now starting on the upcoming decision of the California State Land Commission on granting PG&E a permit to conduct this survey. I believe it is essential that this survey be conducted, with three crucial conditions being met.

A 3-D offshore survey is fundamentally important to precisely locate the faults that could produce earthquakes. More importantly, we need to understand the full vertical and horizontal extent of each fault and how various faults connect with one another. The size, location and connectivity of these faults relate directly to the maximum earthquake they can generate and thus the strength of ground shaking at the power plant. Properly conducted, a 3-D seismic survey is unrivaled at providing a detailed image of these features.

The crucial conditions to be met are, first, that the survey is properly designed. The scale of the survey must be sized to cover only the geologic structures relevant to damaging earthquakes. Comments from the Independent Peer Review Panel, on which I sit as this county’s representative, have addressed the overall footprint of the survey and the panel is further considering the details of the survey design.

Second, impacts to marine life must be absolutely minimized. These impacts can be addressed by timing the survey to avoid migration and breeding seasons and having appropriate observers on board, so that operations are suspended if marine mammals are nearby. The issues of marine life disturbance by survey activities have been extensively studied in recent years and deserve the utmost consideration in the upcoming discussion of the EIR.

Finally, the financial impacts to commercial fishing operators must be properly compensated. The full evaluation of short and medium term loss of access and disturbance to fish stocks is essential. The experience of recent offshore activities, such as the placement of trans-oceanic cables, should serve as a model to determine fair compensation.

No matter what opinion one has of nuclear power generation in general, or the Diablo Canyon plant in particular, the knowledge to be gained from this 3-D seismic survey is crucial to a greater understanding of our region’s complex geology. That, in turn, will inform a more robust understanding of risks to the safety of Diablo Canyon power plant, a critical feature of our county’s environmental and economic landscape.

Bruce Gibson is the 2nd District supervisor for San Luis Obispo County. He holds a Ph.D. in geophysics, having specialized in seismic reflection survey techniques, and serves on the Independent Peer Review Panel convened to comment on PG&E’s seismic survey program.

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