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.
If you live or work in the San Francisco Bay region, this handbook explains why you should be concerned with earthquakes, what you can expect during and after a quake, and what you need to do beforehand to be safe and reduce property damage.
With high property damage, loss of life and fire damage were relatively low. Why? The legal system encourages builders to follow code, the electrical grid was shut down early, and emergency response management was very effective.
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.
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.
Preparing for earthquakes along this important fault requires studying the history of its movement and its geology, as well as understanding how society has built the area around it.
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.
History of the Hawaiian Volcano Observatory (HVO), established in 1912, including an overview of Hawaiian volcanic processes and USGS monitoring techniques.
Homepage for tsunami research with links to information and images on basics, tsunamis in the Pacific Northwest, the 1998 Papua New Guinea tsunami, research on specific tsunamis, and animations in various formats.