24-Hour Aftershock Forecast Map
The U.S. Geological Survey provides maps showing the probability of earthquake shaking in the next 24 hours in California. The maps illustrate the change in earthquake probability during aftershock and possible foreshock sequences. The maps are not intended to be used to predict an upcoming earthquake, however based on previous sequences, an increase in probability will be seen before about half of California’s larger earthquakes. The maps are updated at least once an hour.