Real-time earthquake maps of the conterminous U.S., Alaska, Hawaii, and Puerto Rico displaying magnitude and location of earthquake activity in the past hour, past day, and past week.
Near-real-time maps of location, ground motion, and shaking intensity of earthquakes in California and Nevada for the past hour, past day, and past week and links to other earthquake information.
Information on world earthquake activity with links to facts and lists on large earthquakes, earthquake e-mail notification, hazards and preparedness, educational links, news and highlights and other seismic information.
Description of intensity and magnitude as indicators of the size of an earthquake and the levels of severity measured on the Richter Magnitude Scale and the Modified Mercalli Intensity Scale.
Description of earthquake that was felt in Joshua Tree region (1999) and links to earthquake summary, shaded relief map, aerial photos of the rupture zone, shaking intensity maps, damage reports, and seismograph network map.