Earthquake Planning Scenarios for California

The California Geological Survey and U.S. Geological Survey started developing earthquake scenarios for planning purposes in 1980. Earthquake scenarios are example events chosen for emergency planning exercises. They are usually developed for specific faults that have the potential to produce significant earthquakes and are intended to depict the potential consequences of such earthquakes. They are not necessarily the largest or most damaging earthquakes possible, but are both large enough and likely enough to be included in emergency response plans.

An earthquake scenario is developed assuming that a particular fault ruptures over a certain length, producing a certain magnitude earthquake. The earthquake magnitude that a fault is capable of producing and its average recurrence interval are estimated based on fault dimensions, slip rate, and rupture style (strike-slip, normal, or reverse faulting). Once an earthquake scenario is developed, ground motions are predicted for a region surrounding the fault using ground motion prediction equations. Surface fault rupture and liquefaction and landslide potential may be evaluated for the scenario earthquake. Some scenarios include estimates of economic losses, damage to infrastructure, and social impact associated with the potential earthquake.