Californians are being told to brace for 'the big one' - a massive earthquake that typically occurs every 400 to 600 years and could leave thousands dead or homeless.
An earthquake scientist has added to claims the dreaded event is overdue, warning the San Andreas fault is 'locked, loaded and ready to roll'.
The fault is the longest in California and one of the state's most dangerous.
Thomas Jordan, director of the Southern California Earthquake Centre, said the fault has been 'too quiet' since 1857.
This is when the last big quake to strike a southern section rippled from Monterey County to the San Gabriel Mountains near Los Angeles with a magnitude of 7.9 on the Richter scale.