San Onofre Earthquake Risk


Earthquake Risk

Earthquake Map within 10/50 miles of San Onofre San Onofre was redesigned for a 7.0 earthquake, but sits near faults capable of 8.0+ earthquakes 10 times larger, 32 times stronger, and long overdueSee USGS earthquake calculator.

Nelson Mar, PhD (former Senior Engineer for the original design of San Onofre Units 2 & 3), said San Onofre is not designed for current earthquake or tsunami risks. See 3/27/12 Irvine City Council meeting video.

Over the next 30 years the probability of a major earthquake occurring in Southern California is 60% and 67% in the San Francisco Bay area.

USGS: “…no scientists have EVER predicted a major earthquake.”

USGS M5+ earthquakes

They do not know how and they do not expect to know how any time in the foreseeable future.   Major earthquakes can occur on what are predicted to be minor faults. Based on scientific data, only probabilities can be calculated for potential future earthquakes. U.S. Geological Survey (USGS)

    • “Information about how big an earthquake’s going to be may not be in the earth’s crust BEFORE the earthquake begins” says USGS seismologist Dr. Lucy Jones.

Many seismic countries, however, have research programs based on identifying possible precursors to major earthquakes. This includes the study of dilatancy, how rocks crack and expand under the increased stress associated with the earthquake. Some major earthquakes, but not all, are heralded by the occurrence of foreshocks. which can be detected by dense local monitoring networks. Other instruments can measure changes in the levels of radon gas, electrical and magnetic properties, velocity changes of seismic waves and changes in topography. Long term monitoring and examination by these sensors is required as some or all of these factors may change due to the opening of cracks PRIOR to the earthquake. All attempts to predict earthquakes have, however, been generally considered as failures and it is unlikely that accurate prediction will occur in the near future.  Efforts will, instead, be channelled into hazard mitigation. Earthquakes are difficult or impossible to predict because of their inherent random element and their near-chaotic behaviour.  British Geology Survey FAQS

    • The Earth’s natural systems are not static… This is why I personally feel we need to regularly update the scientific data we use to inform our regulatory approach so that our nuclear facilities are adequately protected against unanticipated events”, said NRC Chairman Macfarlane at the November 6, 2012 INPO CEO conference, in reference to the Fukushima nuclear disaster.

Building design limitations due to ground motion unpredictibility

Professor Thomas Heaton of Caltech’s Earthquake Engineering Research Lab, reveals limitations in designing structures to protect against large earthquakes. Every earthquake has different dynamics and affects different types of construction differently.  “All tall buildings are designed to be flexible, but here’s the rub,” Heaton said. “People talk about a building designed for an 8 [magnitude], as if anybody has a good idea of what the actual ground motion would be in an 8. There’s tremendous variation from one place to another.” If you “put a really large quake under downtown L.A., 7-plus, it could be a true nightmare.” L.A. Times, Earthquakes on the brain, April 1, 2014.

Fracking on the Newport-Inglewood Fault

Fracking can trigger earthquakes

Correlation between earthquake frequency and volume of contaminated waste injected. Rocky Mountain Arsenal Well, Colorado 1962-1965

Correlation between earthquake frequency & volume of contaminated waste injected. Rocky Mountain Arsenal Well, Colorado 1962-65

Earthquakes can be triggered by any significant perturbation of the hydrologic regime.  In areas where potentially active faults are already close to failure, the increased pore pressure resulting from fluid injection, or, alternatively, the massive extraction of fluid or gas, can induce sufficient stress and/or strain changes that, with time, can lead to sudden catastrophic failure in a major earthquake.

Source: Triggered Earthquakes and Deep Well Activities, Craig Nicholson and Robert L. Wesson, 1992.


Lessons learned from the March 11, 2011 9.0 Tohoku, Japan earthquake.

    • Seismologists across the globe were surprised by the magnitude of shaking that occurred in the segment of fault responsible for the Tohoku quake. Japanese scientists had not believed a quake of such intensity could occur in that area, which in turn impacted tsunami strength estimates.
    • Insights gained from the Tohoku earthquake are leading scientists to re-evaluate the way they’ve assumed many other major faults are segmented. This may end up altering some hazard analyses for the West Coast, and will contribute to improved scenario modeling, building code development, and public warnings about tsunami threats.
    • An unparalleled amount of strong ground motion data were recorded.
    • Many cases of liquefaction were witnessed and filmed for the first time. Liquefaction occurs when soil loses strength and stiffness due to an applied stress like an earthquake and behaves like a liquid, often causing damage to structures and infrastructure.
    • Even though the Japanese had planned and were well-prepared for a 200- or 300-year tsunami, they were not prepared for the 1000-year tsunami (an event that’s likely to occur just once every 1,000 years) that came instead. Consequently, Japan is currently updating its tsunami disaster plans for all of its coastal areas and requiring that all plans take evidence from paleo-tsunami deposits into consideration.
    • Paleo-tsunami deposits are the sand and mud that tsunamis leave behind. By studying deposits from recent events like the March 11 tsunamis, scientists are able to develop criteria for what those deposits look like and use them to examine coastal areas for records of tsunamis that struck centuries back. They can tell when tsunamis occurred and how far inland they reached by looking at the evidence left behind.  USGS coastal and marine geologists Bruce Jaffe, Bruce Richmond, and Rick Wilson have worked with Japanese scientists over the past year to study these deposits in Japan. Said Jaffe, “Japan has learned from this tsunami that it’s necessary to look at the geologic evidence for tsunamis in conjunction with the current understanding of earthquake potential to accurately assess the future tsunami hazard.” He explained that “Each tsunami brings its own sand and mud. Japan recognizes the value of using the very rich record of past tsunamis to help us understand the hazard for future tsunamis.”
    • The United States is also conducting its own paleo-tsunami deposit studies in California, Alaska, the Caribbean, Puerto Rico, and the Virgin Islands to better understand the tsunami risk in those areas.

Ratepayers must pay $64 million in new seismic studies.

Lessons learned about strike-slip faults from 8.6 East Indian Ocean earthquake.

    • On April 11, 2012, an 8.6 earthquake struck the East Indian Ocean along a strike-slip fault – the largest earthquake ever recorded on a strike slip and 10 times larger than any previously recorded strike-slip quake.
    • A large earthquake in one part of the globe can trigger earthquakes elsewhere. In the 6 days after the quake, the number of earthquakes across the globe that were 5.5 or larger increased nearly five fold. “if you asked any of us if this event is possible a year ago, we would have laughed at you”, said Thomas Heaton, seismologist at California Institute of Technology. 9/28/2012, USGS 9/26/2012, Nature 2012

San Onofre and Diablo Canyon nuclear plants are located within the “Ring of Fire”.Ring of Fire

The “Ring of Fire“, also called the Circum-Pacific belt, is the zone of earthquakes surrounding the Pacific Ocean. About 90% of the world’s earthquakes occur there.

See animation of 2011 global 6.0+ earthquakes (using USGS data) and more maps below.

Mexico’s recent 7.4 earthquake (03/20/2012) was 2.5 times larger and 4 times stronger than what San Onofre is designed for. Japan’s Fukushima Daiiachi nuclear meltdown began after a 9.0 earthquake.

Lessons learned about length of a fault.

Known length of a fault is not always a predictor of magnitude as in the 1952 Kern County 7.5 earthquake.

Kern County 7.5 Earthquake 1952

Vertical fracture on the northeast side of Bear Mountain, along the White Wolf Fault. At this location, a vertical displacement of 60 cm (2 ft) and a horizontal (left-lateral) displacement of 45 cm (1.5 ft) were measured along the break. Photo: University of California, Seismographic Station

Seismic evaluations are not required before license renewal.

San Onofre was originally licensed to shut down in 2013, but was extended to 2022. The plant was designed in 1973 for a 40 year lifespan. In 2013 Southern California Edison plans to ask for an extension to 2042. A comprehensive seismic analysis has not been conducted on San Onofre since 1995, according to an April 2012 Government Accountability Office report.

Magnitude ComparisonMaps:

Map Southern California Earthquake Faults

California Earthquake Probabilities Map -


  USGS US %G Force Hazard Map

Global Earthquakes (1900-1999)

Global Earthquakes 1900-1999

Source USGS   

2011 Global 6.0+ earthquakes plotted and animated with sound

SONGs and Scripps Seismic Submarine
San Onofre disaster

Our worst nightmare every time the earth shakes in Southern California



Forecasting California’s earthquakes – What can we expect in the next 30 years (USGS)
The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2)
California Institute of Technology (Caltech)
Southern California Earthquake Center (SCEC)
Nuclear Regulatory Commission
LA Times “50 New California Faults” 04/28/2010
Earthquake Country Information
Kern County Earthquake 7.5 (SCEC)
Significant Earthquakes & Faults in Southern CA (SCEC)
Earthquake Facts and Statistics (USGS)
British Geological Survey FAQS
Forecasting California’s earthquakes – What can we expect in the next 30 years (USGS)
The Uniform California Earthquake Rupture Forecast, Version 2 (UCERF 2)
California Institute of Technology (Caltech)
Southern California Earthquake Center (SCEC)
Nuclear Regulatory Commission
LA Times “50 New California Faults” 04/28/2010
Earthquake Country Information
Kern County Earthquake 7.5 (SCEC)
Significant Earthquakes & Faults in Southern CA (SCEC)
Earthquake Facts and Statistics (USGS)
British Geological Survey FAQS


San Onofre Nuclear Generating Station (SONGS)

San Onofre Safety | Nuclear Safety and Cost

Earthquake Risk

Tsunami Hazards, Modeling, and the Sedimentary Record

How Would Large Earthquake Affect San Onofre Nuclear

San Onofre Operators Begin Study On Earthquake Risk

San Clemente, CA Earthquakes | Homefacts

Seismic risk – Keep San Onofre Shut Down! – Friends of the …

San Onofre Nuclear Generating Station



Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s