The Big One may be overdue to hit California, but scientists near LA have found a new risk for the area during a major earthquake.

They claim that if a major tremor hits the area, it could plunge large parts of California into the sea almost instantly.

The discovery was made after studying the Newport-Inglewood fault, which has long been believed to be one of Southern California's danger zones.

The fault runs under densely populated areas, from the Westside of Los Angeles to the Orange County coast.

Major earthquakes on the fault centuries ago caused parts of Seal Beach near the Orange County coast to sink 3ft in just seconds.

In total three quakes over the last 2,000 years on nearby faults made ground just outside Los Angeles city limits sink as much as 3ft.  

Today that could result in the area ending up at or below sea level, said Cal State Fullerton professor Matt Kirby, who worked with the paper´s lead author, graduate student Robert Leeper.

The study showed that land within major Californian seismic faults could sink by 1.5 and three feet instantly.