California's most famous earthquake zone lies atop the San Andreas Fault. Running roughly parallel with the coastline, the fault lies offshore along the northern coast but touches land at Point Reyes National Seashore
and stays inland from San Francisco
The fault, which represents the line of contact between two tectonic plates, produces visible effects in many places through the gradual shifting of landforms. When the shifts come suddenly, they produce earthquakes, such as the famous 1906 San Francisco earthquake. The fault runs 600 miles to the Colorado Desert.