Earthquake Hazards and Risk

Portions of all 50 states and the District of Columbia are vulnerable to earthquake hazards, although risks vary greatly across the country and within individual states. Seismic hazards are greatest in the western United States, particularly in California, Washington, Oregon, and Alaska and Hawaii. In contrast, California has more citizens and infrastructure at risk than any other state because of the state's frequent seismic activity combined with its large population. The United States faces potentially large total losses due to earthquake-caused damage to buildings and infrastructure and lost economic activity. An April 2008 report from the Federal Emergency Management Agency (FEMA) calculated that the average annualized loss from earthquakes nationwide is $5.3 billion, with California, Oregon, and Washington accounting for nearly $4.1 billion (77%) of the U.S. total estimated average annualized loss. A single large earthquake can cause far more damage than the average annual estimate. A Decrease in Estimated Loss? The earthquake caused an estimated $30 billion in total economic damage. Detection, Notification, and Warning

Unlike other natural hazards, such as hurricanes, where predicting the location and timing of landfall is becoming increasingly accurate, the scientific understanding of earthquakes does not yet allow for precise earthquake prediction. Instead, notification and warning typically involves communicating the location and magnitude of an earthquake as soon as possible after the event to emergency response providers and others who need the information. The portable array has progressed across most of the conterminous United States. Outlook

A precise relationship between earthquake mitigation measures, NEHRP and other federal earthquake-related activities, such as earthquake research, and reduced losses from an actual earthquake may never be possible. However, as more accurate seismic hazard maps evolve, as understanding of the relationship between ground motion and building safety improves, and as new tools for issuing warnings and alerts such as ShakeMap and PAGER are devised, trends denoting the effectiveness of mitigation strategies and earthquake research and other activities may emerge more clearly. Without an ability to precisely predict earthquakes, Congress is likely to face an ongoing challenge in determining the most effective federal approach to increasing the nation's resilience to low-probability but high-impact major earthquakes.
Portions of all 50 states and the District of Columbia are vulnerable to earthquake hazards, although risks vary greatly across the country and within individual states. Seismic hazards are greatest in the western United States, particularly in California, Washington, Oregon, and Alaska and Hawaii. California has more citizens and infrastructure at risk than any other state because of the state's frequent seismic activity combined with its large population and developed infrastructure.
The United States faces the possibility of large economic losses from earthquake-damaged buildings and infrastructure. The Federal Emergency Management Agency has estimated that earthquakes cost the United States, on average, over $5 billion per year. California, Oregon, and Washington account for nearly $4.1 billion (77%) of the U.S. total estimated average annualized loss. California alone accounts for most of the estimated annualized earthquake losses for the nation.
A single large earthquake, however, can cause far more damage than the average annual estimate. The 1994 Northridge (CA) earthquake caused as much as $26 billion (in 2005 dollars) in damage and was one of the costliest natural disasters to strike the United States. One study of the damage caused by a hypothetical magnitude 7.8 earthquake along the San Andreas Fault in southern California projected as many as 1,800 fatalities and more than $200 billion in economic losses.
Unlike other natural hazards, such as hurricanes, where predicting the location and timing of landfall is becoming increasingly accurate, the scientific understanding of earthquakes does not yet allow for precise earthquake prediction. Instead, notification and warning typically involve communicating the location and magnitude of an earthquake as soon as possible after the event to emergency response providers and others who need the information.
A precise relationship between earthquake mitigation measures, federal earthquake-related activities such as earthquake research, and reduced losses from an actual earthquake may never be possible. However, as more accurate seismic hazard maps evolve, and as understanding of the relationship between ground motion and building safety improves, trends denoting the effectiveness of mitigation strategies and earthquake research and other activities may emerge more clearly. Without an ability to precisely predict earthquakes, Congress is likely to face an ongoing challenge in determining the most effective federal approach to increasing the nation's resilience to low-probability but high-impact major earthquakes.