The San Andreas Fault is an extremely well known fault running roughly 800 miles through California. A fault is anywhere that slippage has caused rocks to split and create a fracture or crevice. The San Andreas Fault is a 10-mile deep type of strike slip fault, meaning that the direction of grinding is horizontal, as opposed to a normal fault in which the rocks grind in a near-vertical direction. It’s along two tectonic plates that were responsible for the famous San Francisco earthquake in 1906. When the sides of the fault get pinned while rubbing against each other, tension builds until it breaks causing an earthquake.
This video helps one visualize how a strike-slip fault works:
http://www.youtube.com/watch?v=MrrLJ4vXHCs
This video shows a more detailed depiction of the San Andreas Fault specifically:
http://www.youtube.com/watch?feature=player_embedded&v=tIuk2blBzHs#t=16
The sides of the fault are sliding against each other at a reasonably steady rate of two and a half inches every year. It has been sliding for the past 28 million years, since it’s inception. Calculations estimate that in another 25 million years California will be a completely contorted unrecognizable mess due to the rate of slippage. It is also understood that the current appearance of California is drastically different than it once was due to the fault line.
The most significant characteristic of the San Andreas Fault is the fact that it runs over the gap between tectonic plates yet is on dry land. This is not usually the case with faults like this and it allows for greater research opportunity than if it were along the seafloor.
Sources:
Lynch, David K.. “Information and resources about the San Andreas Fault.” San Andreas Fault Homepage. N.p., n.d. Web. 13 Sept. 2013. <http://www.sanandreasfault.org/Information.html>.
“IRIS – What are the 4 basic classes of faults?” IRIS – Incorporated Research Institutions for Seismology. N.p., n.d. Web. 13 Sept. 2013. <http://www.iris.edu/hq/programs/education_and_outreach/animations/2>.
