A powerful offshore magnitude 8.2 earthquake shook Mexico City on September 7, one of the largest quakes to hit Mexico in the last century. This was followed on September 19 by a magnitude 7.1 shaker that struck central Mexico, collapsing buildings in plumes of dust and killing more than 300 people. Two more earthquakes shook southern Mexico on Saturday, September 22, further upsetting a country still coming to grips with the devastation from the strong temblors earlier in the month.
Here in California, we are told to get ready for "The Big One", a possible 9.0 Fukushima-like earthquake. Unfortunately, a quake of this magnitude would be compounded by the threat it poses to PG&E's Diablo Canyon nuclear power plant. Originally designed to withstand a magnitude 6.75 earthquake and later reconstructed to tolerate a magnitude 7.5 quake, the nuclear plant's tolerances underestimate the true seismic potential of today's mega-thrust shakers.
Additionally, a previously well-documented zone of faulting called the Diablo Cove Fault extends through the foundation, under the power plant's Unit One turbine generator and reactor containment vessel. The east-west trending Diablo Cove Fault runs offshore and intersects with the nearby Shoreline Fault which in turn is connected to the Hosgri Fault Line, a component of the San Andreas Fault System. The power stored within this network of seismically linked faults could create an earthquake sufficient to exceed Diablo Canyon’s safeguards.