The San Andreas Fault is a transform fault, that stretches across 800 miles. The San Andreas caused one of the largest earthquakes ever recorded. It splits California into two parts from Cape Mendocino to the Mexican border. In San Francisco in 1906 the earthquakes caused 664 deaths and left more than half the population homeless. The earthquake also left $400,000,000 worth of property damage in its wake. The fault was discovered in 1895 by geology professor Andrew Lawson and was named by him at a lake nearby. After the 1906 earthquake Andrew Lawson was the same person to discover how far the fault actually stretched.
The two plates that make up the fault move past each other a couple inches a year. But that movement is not consistent some years the plates will not move at all. Eventually the tension will become overwhelming and the plates will move a couple feet at once causing an earthquake.
In some places the fault is easier to see than in other areas. In places like Carrizo Plain (San Luis Obispo County) and the Olema Trough ridges and other georgaphic clues allow you to see the actual fault. In other areas the fault has not moved at all and has been covered by brush and rock.
On both sidea of the fault are rocks that are nearly 28 million years old coming from many different areas. “The Salinian block of granite in central and northern California originated in Southern California, and some even say northern Mexico(David K. Lynch).
There are even myths saying that the fault will one day crack and California will float off into the see. That myth has been proven to not be true. There is know given time or exact estimation that can be made to predict when the fault will cause an earthquake.
In Parkfield, California a small town along the fault research has discovered that this particular section along the fault produces large earthquakes about every 22 years. Scientists began to make predictions as to when the next earthquake would hit. Due to these predictions this spot of the San Andreas fault has become one of the most watched areas for large earthquakes.
Some scientists believe the next big quake is in the near future. Scientists believe there has been a large earthquake in the central sector of the fault and the northern sector. But the southern sector has yet to see a quake of the other two sectors magnitude. No one can predict when it will happen.
“The information available suggests that the fault is ready for the next big earthquake but exactly when the triggering will happen and when the earthquake will occur we cannot tell,” Fialko said. “It could be tomorrow or it could be 10 years or more from now (Yuri Fialko).”