San Andreas Fault Line

The San Andreas fault line is located on the west coast of the United States of America. The fault line itself runs from Cape Mendocina, California, all the way down to the Mexican border, covering over 800 miles.

What is it?

The San Andreas fault actually slices through a chunk of California. This is the main reason scientists and society have joked that one day California will break off from the United States and become an island!

Before we analyze the specifics of the San Andreas fault, I think it is important to define a fault line. A fault line, according to Webster’s, is a “fracture of the continuity of rock”. Simply put, under the earth’s surface, there is a fracture along the rock. This fracture is called a fault line. The San Andreas fault line is where the North Atlantic Plate touches with the Pacific Plate. These two plates were created through the fault line.


This particular fault line rose to fame in 1906, when the famous San Francisco earthquake occured. While California is known for earthquakes, the San Andreas fault has not yet been capable of causing routine extreme earthquakes. The more dangerous fault lines would be found where two tectonic plates actually slide over top of one another.

Believe it or not, this particular fault line is over 28 million years old!

Visiting the Fault Line

Tourists and visitors flock to the fault line every year. Many expect to see a crack through the earth, but rather what you will find is a “fault zone” often covering several miles.

In some areas, you may be driving right through the fault zone and not even know it. If you do want to see some signs of the fault line or fault zones, there are some great places where you can do just that.

The Carrizo Plain and the Olema Trough are both places where the fault is easy to see. Here you can view pressure ridges and land scarps.

Another neat fact about the San Andreas fault, is that it is one of the only large fault lines that you can visit and see on land. Most of the fault lines on eart occur under the ocean, and are not visible to us.

If you are first time visitor wanting to get the most of your visit, consider one of the guided tours offered at several parks. Some of the parks located on or near the fault line are: Sonny Bono Wildlife Refuge; Wister Unit, Imperial Wildlife area; and Salton Sea State Recreation Area.

Don’t be afraid to visit the beautiful fault zones, and be sure to take your camera! There are beautiful and unique views here that won’t find anywhere else!