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.
Evansville, Indiana, is near the Wabash Valley and New Madrid seismic zones and has experienced minor damage from earthquakes in the past 200 years. This fact sheet describes three types of USGS earthquake hazard maps for Evansville and surrounding areas.
National Strong-Motion Program home page with links to program news, recent events, and datasets of digitized accelerograms downloadable as PC (*.zip) and Unix (*.tar.z) files, data processing, stations, research, publications, and personnel.
Overview of volcano hazards in California with links to monitoring data including earthquakes and deformations, long-term outlook, volcano hazards in the area, USGS response plan, image gallery, monitoring and topical studies, publications and references.
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.