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.
Information on the Earth's crust with a contour map of the thickness plus links to a global crustal database, a global crustal model - CRUST 5.1, and regional crustal models.
Fact sheet describing plans for a San Andreas Fault Observatory at Depth (SAFOD) by drilling into the fault to install instruments for long-term monitoring near the location of the magnitude 6 Parkfield earthquakes.
Annotated list of resources about the great earthquake of 1906, which caused significant devastation in and around San Francisco, California, compiled for the 100th anniversary of the disaster.
Online booklet giving an introduction to the concept of plate tectonics and complements the information on the map This Dynamic Planet published in 1994 by the U.S. Geological Survey (USGS) and the Smithsonian Institution.