Earthquake forecasting

Earthquake forecasting is a branch of the science of geophysics, primarily seismology, concerned with the probabilistic assessment of earthquake occurrence within a given limits of time, location and magnitude. Often confused with earthquake prediction, earthquake forecasting has a distinct objective. While earthquake prediction aims to specify the exact time, location, and magnitude of a future event to enable immediate emergency action, earthquake forecasting focuses on the probabilistic assessment of future earthquakes over broader windows. Because of this probabilistic framework, it is considered scientifically feasible and forms the foundation of operational earthquake forecasting. Both forecasting and prediction of earthquakes are distinguished from earthquake warning systems, which, upon detection of an earthquake, provide a real-time warning to regions that might be affected.

In the 1970s, scientists were optimistic that a practical method for predicting earthquakes would soon be found, but by the 1990s continuing failure led many to question whether it was even possible. Demonstrably successful predictions of large earthquakes have not occurred, and the few claims of success are controversial. Consequently, many scientific and government resources have been used for probabilistic seismic hazard estimates rather than prediction of individual earthquakes. Such estimates are used to establish building codes, insurance rate structures, awareness and preparedness programs, and public policy related to seismic events. In addition to regional earthquake forecasts, such seismic hazard calculations can take factors such as local geological conditions into account. Anticipated ground motion can then be used to guide building design criteria.