The San Andreas FaultRyan Holec

San Andreas Fault

Past Occurrences of the Fault

Last large earthquake on southern San Andreas occurred in 1857.

1857 Fort Tejon Earthquake ruptured 225 miles of the fault.

1906 massive earthquake moved trees, branches, and bushes 21 feet from original spot. The biggest offset ever recorded, the fault moved north.

1994 a earthquake killed 51 people.

Present Day Reserch

San Andreas Fault is a transform boundary.

Runs from Gulf of California to San Francisco area.

Made up of Pacific Plate sliding against the North American Plate.

800 miles long Extends nearly 10 miles deep Studies show that big

earthquakes will occur about every 150 years.

GPS systems are used to measure the relative motion between the opposite sides of the fault. This shows a movement of about 1 to 2 inches a year.

Transform boundaries are where two tectonic plates slide past one another.

Over years two points on opposite sides of the fault will be at different degrees latitude.

Fault Line Earthquakes

For the past few thousand years earthquakes on the San Andreas Fault have been occurring at intervals of about 150 years. The last big earthquake on the southern end was in 1857, and it has been roughly 150 years. This means the next massive earthquake could occur in the next decade or sooner. The northern earthquake happened in 1906, and it has been around 105 years since that earthquake. This means the next Earthquake will happen in about 50 years.

The southern end of the fault is made up of harder material so it may take longer for there to be a earthquake down there. The northern is softer and can crack more easily.

Prediction on the Fault

My prediction is that the fault will keep moving 2 inches per year. I predict the southern end of the fault line will have a massive earthquake within 10 years and the northern end will have one around 50 years from now. When these massive earthquakes occur they have sudden releases of pressure that makes it jump farther than they would in a normal year. GPS readings verify that the movement of the plates are continually moving. So, over a long, long time the plates will eventually run past each other and the southern part of California will be an island or a peninsula.