According to seismologists, the 9.0-magnitude quake that hit Japan in 2011, killing thousands of people and damaging the Fukushima nuclear power plant was caused by a snap in a portion of a fault experts believed wouldn't likely rupture.
The new study based on research collected in the aftermath of that quake suggests California's San Andreas Fault could too. The research focused on a section of the fault called a creeping segment. It's about 50 miles east of the coastline, between Paso Robles and Monterey.
The creeping segment, much like Japan's, was long believed to have been slipping slowly and steadily, releasing pressure as tectonic plates shifted. But researchers now believe it, too, has the potential to behave like locked segments, which build up stress over time and then rupture.
"In order for a quake to happen, the fault has to be locked and the strain has to be building up over years, said Caltech seismologist Kate Hutton.
Hutton said while the research is still in the early stages, it begs the question of what would happen if a quake that began in San Francisco on the San Andreas Fault continued into Southern California.
"The answer is that it would be obviously a bigger earthquake than each side would have, but more it's like two earthquakes that occurred at the same time and prevented the emergency services people from responding as they would if there was only one," said Hutton.
Hutton said though the research indicates a mega-quake would be very rare, occurring once in about a 1,000 years, it could result in the loss of some of our coastline.
"We're not going to sink. But places like Malibu, where they have landslides all the time, that stuff might fall in if you shake it hard enough," said Hutton.