Earthquake Hazards Program
This “ShakeMap” is a representation of the shaking produced by the ShakeOut Scenario earthquake. The colors represent the Modified Mercalli Intensity with the warmer colors representing areas of greater damage (from figure 1.2).
This is the initial publication of the results of a cooperative project to examine the implications of a major earthquake in southern California. The study comprised eight counties: Imperial, Kern, Los Angeles, Orange, Riverside, San Bernardino, San Diego, and Ventura. Its results will be used as the basis of an emergency response and preparedness exercise, the Great Southern California ShakeOut, and for this purpose we defined our earthquake as occurring at 10:00 a.m. on November 13, 2008. As members of the southern California community use the ShakeOut Scenario to plan and execute the exercise, we anticipate discussion and feedback. This community input will be used to refine our assessment and will lead to a formal publication in early 2009.
Our goal in the ShakeOut Scenario is to identify the physical, social and economic consequences of a major earthquake in southern California and in so doing, enable the users of our results to identify what they can change now—before the earthquake—to avoid catastrophic impact after the inevitable earthquake occurs. To do so, we had to determine the physical damages (casualties and losses) caused by the earthquake and the impact of those damages on the region’s social and economic systems. To do this, we needed to know about the earthquake ground shaking and fault rupture. So we first constructed an earthquake, taking all available earthquake research information, from trenching and exposed evidence of prehistoric earthquakes, to analysis of instrumental recordings of large earthquakes and the latest theory in earthquake source physics. We modeled a magnitude (M) 7.8 earthquake on the southern San Andreas Fault, a plausible event on the fault most likely to produce a major earthquake. This information was then fed forward into the rest of the ShakeOut Scenario.
The damage impacts of the scenario earthquake were estimated using both HAZUS-MH and expert opinion through 13 special studies and 6 expert panels, and fall into four categories: building damages, non-structural damages, damage to lifelines and infrastructure, and fire losses. The magnitude 7.8 ShakeOut earthquake is modeled to cause about 1800 deaths and $213 billion of economic losses. These numbers are as low as they are because of aggressive retrofitting programs that have increased the seismic resistance of buildings, highways and lifelines, and economic resiliency. These numbers are as large as they are because much more retrofitting could still be done.
The earthquake modeled here may never happen. Big earthquakes on the San Andreas Fault are inevitable, and by geologic standards extremely common, but probably will not be exactly like this one. The next very damaging earthquake could easily be on another fault. However, lessons learned from this particular event apply to many other events and could provide benefits in many possible future events.
Download this report in high resolution as a 312-page PDF file (of2008-1150.pdf; 20.7 MB).
Download this report in standard resolution as a 312-page PDF file (of2008-1150small.pdf; 9.8 MB).
The Appendixes for this report consist of the following ten papers:
You can also go to the Appendixes folder. This folder contains the PDFs of Appendixes A–J as well as a .zip archive file of all ten (appendixes folder; 11 files, 415 MB total).
For questions about the content of this report, contact Lucile Jones
Suggested citation and version history
USGS Circular 1324/CGS Special Report 207 The ShakeOut Earthquake Scenario—A Story That Southern Californians Are Writing by Suzanne Perry, Dale Cox, Lucile Jones, Richard Bernknopf, James Goltz, Kenneth Hudnut, Dennis Mileti, Daniel Ponti, Keith Porter, Michael Reichle, Hope Seligson, Kimberley Shoaf, Jerry Treiman, and Anne Wein
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