Why is the San Andreas Fault so notorious?

The San Andreas is considered "the 'master' fault of an intricate fault network," the Geological Survey said. It's the fault responsible for the 1906 San Francisco earthquake, which killed about 700 people.

The 800-mile-long fault is the boundary between the Pacific Plate and North American Plate. And because the Pacific Plate shifts about 2 inches a year, the Geological Survey said, Los Angeles and San Francisco will become next-door neighbors (though not for about 15 million years).

So while it's impossible for the San Andreas to sweep California out into the ocean, the Geological Survey said, southwestern California is slowly -- very slowly -- sliding past the rest of the state toward Alaska.