What is the probability that an earthquake is a foreshock to a larger earthquake?
Worldwide the probability that an earthquake will be followed within 3 days by a large earthquake nearby is somewhere just over 6%. In California, that probability is about 6%. This means that there is about a 94% chance that any earthquake will NOT be a foreshock. In California, about half of the biggest earthquakes were preceded by foreshocks; the other half were not. At this time, we cannot tell whether or not an earthquake is a foreshock until something larger happens after it... so only in retrospect.
What is the likelihood of a large earthquake at location X? Is it safe to go to X since they've been having a lot of earthquakes lately?
What is seismic hazard? What is a seismic hazard map? How are they made? How are they used? Why are there different maps, and which one should I use?
Early on the morning of August 24, 2014, Loren Turner was awoken by clattering window blinds, a moving bed, and the sound of water splashing out of his backyard pool. He experienced what is now named the “South Napa Earthquake.”
New Audiences, New Products for the National Seismic Hazard Maps
A new report issued by the American Red Cross and the U.S. Geological Survey documents the Chilean response and recovery efforts following the Feb. 2010 magnitude 8.8 earthquake and the lessons that California should learn from this disaster.
Friday's magnitude-5.2 earthquake in southern Illinois is a reminder that earthquakes are a national hazard.
A new geologic map of surficial deposits in the nine-county San Francisco Bay region that can be used to evaluate earthquake hazards has been released in digital form by the U.S. Geological Survey in Menlo Park.
USGS map displaying intensity of potential ground shaking from natural and human-induced earthquakes. There is a small chance (one percent) that ground shaking intensity will occur at this level or higher. There is a greater chance (99 percent) that ground shaking will be lower than what is displayed in these maps.
USGS map displaying potential to experience damage from a natural or human-induced earthquake in 2016. Chances range from less than one percent to 12 percent.