Ground shaking caused by the sudden release of accumulated strain by an abrupt shift of rock along a fracture in the earth or by volcanic or magmatic activity, or other sudden stress changes in the earth.
Information on earthquake activity, earthquake science, and earthquake hazard reduction with links to news reports, products and services, educational resources for teachers, glossary, and current U.S. earthquake activity map.
Answers to a wide variety of questions (FAQs) about earthquakes, such as dictionary of terms, earthquake activity and probabilities, common myths, faults, plate tectonics, and earthquake measurement techniques.
Search interface allowing searches of earthquake databases by various parameters including date, depth, intensity, area, and magnitude and download data in a variety of formats.
National seismic hazards maps, global seismic hazards map, predictive intensity maps, shaking hazards maps and probabilities for California, and a variety of fact sheets on earthquakes.
Place to provide information about ground shaking associated with significant earthquakes. A questionnaire to let us know what you felt following an earthquake in the United States or in other countries.
Links to various earthquake projects, facts, science fair ideas, earthquake science, becoming an earthquake scientist, image glossary, earthquake facts, and puzzles and games for children.