San Andreas Fault Archives
San Andreas Fault
The topographic texture of western California is controlled by the San Andreas fault system, the tectonic expression of the Pacific plate sliding northwestward along the western margin of the North American plate. Hundreds of miles long and up to a mile wide, the San Andreas Fault Zone has been active since its original development in the Tertiary.
About 10 percent of the present plate motion is compressional, which means horizontal forces are shortening and wrinkling the crust along the fault zone. This movement has created the parallel coastal northwest-southeast mountain ranges such as the Coastal Ranges along California's central coast. Comparatively quiet during the period between the 1906 San Francisco earthquake and the 1989 Loma Prieta event, the fault is again showing activity.
"San Andreas Fault," NationalAtlas.gov
More
- "The San Andreas Fault," by Sandra S. Schulz and Robert E. Wallace, USGS, 1997
- "The San Andreas Fault and the San Francisco Bay Area," web page by by Joe Dellinger
- Maps of Recent Earthquake Activity in California-Nevada - from USGS
- "A walking tour of the Calaveras fault in Hollister, California," by Joe Dellinger - many photos show the effect of building sidewalks, houses and streets across fault lines
August 29, 2007 10:47 PM Caught Our Eye
