Assemblyman Sam Blakeslee lambasted Gov. Arnold Schwarzenegger’s veto of a bill that would have required three-dimensional mapping to explore earthquake fault zones near Diablo Canyon nuclear power plant.
Blakeslee submitted the bill last December, a month after the so-called Shoreline Fault was discovered less than a mile offshore from Diablo.
The bill would have ordered Diablo Canyon’s owner, Pacific Gas and Electric Co., to use the latest high-definition technologies to map the fault, including a technique called three-dimensional geophysical reflection mapping. The state was then to use that information to make recommendations on whether seismic strengthening was needed at the plant.
“The governor and I have crossed swords a number of times,” Blakeslee said in a telephone interview with The Tribune. “I see this largely as an effort for him to tell me that there is a cost for being independent-minded and not doing as told.”
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In his veto message, Schwarzenegger called the bill unnecessary because of previous legislation that recommended a 3-D study of fault zones at Diablo Canyon.
Schwarzenegger pointed to a bill signed in 2006 that required a study by the California Energy Commission of seismic vulnerability of Diablo. That study recommended that PG&E conduct three-dimensional imaging.
Blakeslee’s bill would have made it a legal requirement.
“I’m optimistic that (PG&E) will take this course of action on their own even without legislation, but if they don’t, I’m prepared to bring this bill back next year,” Blakeslee said. “This is too important of an issue to let the governor’s veto stand in the way of the safety of my community.”
Emily Christensen Archer, a PG&E spokeswoman, said the company conducts regular seismic surveys of the Central Coast. “We are evaluating whether we will incorporate 3-D surveys, as well as other technologies, into our next round of seismic updates,” she said in an e-mail.
The Shoreline Fault is a strike-slip fault, meaning the sides move horizontally, and its tsunami potential is considered low.
The seismic safety of Diablo Canyon has always been a concern, given the many faults that crisscross the Central Coast. Concern heightened in July 2007 when a powerful earthquake in Japan knocked the world’s largest nuclear power plant off line.
Blakeslee pointed to that incident, saying that the lack of seismic retrofit work on the Japanese plant resulted in $12 billion in new costs to ratepayers.
“We want to be sure that we are ready for the next earthquake, and we want to know the size of the fault so we know the potential size of that quake,” he said, referring to the Shoreline Fault.
A 3-D study could cost anywhere from $3 million to $10 million, Blakeslee said.
PG&E maintained last November when the new fault was discovered that it didn’t pose a threat to the plant’s operational safety. The fault is estimated to be from nearly two miles to more than eight miles below the Earth’s surface and from nine to more than 15 miles long and could intersect the Hosgri fault. That fault is 68 miles long and about three miles offshore.