Most of us have seen disaster movies like “A View to a Kill” or “San Andreas” where in the first a criminal thinks he can trigger the San Andreas Fault to collapse and the coastal part of California will fall into the Pacific Ocean with all the huge consequences that will have.

Well, that is the movie. So, what is the real story? We will tell you here.

California's San Andreas FaultThe San Andreas Fault is the sliding boundary between the Pacific and North American Plates. It slices California in two from Cape Mendocino to the Mexican border. As is Bodega Bay, San Diego, Los Angeles, and Big Sur are on the Pacific Plate. San Francisco, Sacramento, and the Sierra Nevada are on the North American Plate.

The San Andreas Fault is what is called a transform fault. It can be best understood with this analogy: Place two slices of pizza on a table, slide them past one another where they touch along a common straight edge, where one will end up above the other. Bits of pepperoni from one side crumble across the point they touch along a common straight edge, where one will end up above the other. Bits of pepperoni from one side crumble across the point where they touch the other slice. The same thing happens with the fault, and the geology and landforms along the mighty rift are very complicated.

Most fault lines are not visible on the surface, but the San Andreas Fault shows itself in multiple locations, which is unique. In places like the Carrizo Plain in San Luis Obispo County the fault is easy to see as a series of scarps and pressure ridges.
California's San Andreas Fault
California's San Andreas Fault

At Gorman in Northwest Los Angeles County, the San Andreas Fault is visible right next to the road with rocks of the Pacific Plate (gray rocks on the left side) and the North American Plate (tan rocks on the left side of the fault) and the North American Plate (the right side of the fault). There are very few places on Earth where you can see two plates in contact like this.

At Bodega Bay, the easiest way to experience the fault is to look south toward Tomales Bay. All the way from Bodega Bay to the bottom of Tomales bay is right on top of the San Andreas Fault though. If you make the trip down highway 1 and drive from Point Reyes Station to Stinson beach, you will drive right on top of the fault. On the way you can enjoy the Olema Valley and the Golden Gate National Recreation Area if you like hiking. The San Andreas Fault is an earthquake zone and scientists predict that there will be earthquakes to come so normal vigilance is prudent all along the San Andreas Fault, also in Bodega Bay. If you’re not familiar with what to do in case of an earthquake, the CDC guidelines can be found here.

For anyone interested in knowing more, here are some useful links:

Field Guide to the San Andreas Fault