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.
Links to geologic information on western states: Alaska, Arizona, California, Hawaii, Idaho, Nevada and Oregon including information on coastal and marine geology, mineral resources, earthquakes, landslides, earthquake hazards and geologic maps.
Description and uses of the Ocean Bottom Seismometer; a self contained data-acquisition system which free falls to the ocean floor and records seismic data generated by airguns and earthquakes.
U.S. Department of the Interior |
U.S. Geological Survey