ShakeOut Earthquake Scenario

Science Center Objects

A modeled probable earthquake scenario based on the most comprehensive scientific research analysis done to understand the impacts and implications of a hypothetical but realistic 7.8 earthquake on the San Andreas Fault. Pairing robust science with state-of-the-art modeling and visualization tools makes ShakeOut an accessible and effective message, in scenario form, to enhance community preparedness and resilience to earthquakes.

The first public product of SAFRR (then the Multi-Hazard Demonstration Project (MHDP)) was the ShakeOut Earthquake Scenario, published in May 2008 and by November of that year becoming the centerpiece of the Nation's largest ever emergency response and public preparedness exercises as The Great Southern California ShakeOut.

The magnitude 7.8 earthquake scenario served as the scientifically credible basis of the largest earthquake drill in United States history involving over 5,000 emergency responders and disaster recovery agents and the participation of over 5.5 million citizens. The ShakeOut Scenario described what would happen during and after a magnitude 7.8 on the southernmost 300 km of the San Andreas fault, a plausible event on the fault most likely to produce a major earthquake. An earthquake like this - large enough to cause strong shaking over much of southern California - is inevitable and understanding its impacts is an important step in preparing for the event.

The ShakeOut Scenario considered a range of effects from the direct physical impacts to the long-term, social, cultural, and economic consequences. The ShakeOut Scenario also identified factors that will determine whether the event would be a disaster or a catastrophe, that is, whether the event would disrupt southern California for a few years, or for decades. This unprecedented project brought together a diverse collaboration of more than 300 scientists, academics, engineers, industry professionals, emergency managers, and public servants.

The USGS and its partners deliver a number of resources and tools, including videos, maps, and animations that have been created to visually convey aspects of the ShakeOut Scenario earthquake and its impacts. These tools, all available at, enable emergency responders, government officials, scientists, and residents to identify the most likely damages and problems, and thus make the best possible decisions.

ShakeMaps, for instance, provide near-real-time maps of ground motion and shaking intensity following significant earthquakes. These maps are used by federal, state, and local organizations, both public and private, for post-earthquake response and recovery, public and scientific information, as well as for preparedness exercises and disaster planning.


ShakeOut Scenario Supplementary Reports: