At 10:17 Oct 17, 2013, 9.5 million people across California are expected to drop cover and hold. It’s part of California’s annual earthquake drill – The Great California Shakeout.

The event comes at time when scientists are warning a large-scale earthquake is long overdue.

One potentially dangerous earthquake fault located near San Diego is the San Jacinto, known as the most active earthquake fault in southern California, according to Kenneth Hudnut, geophysicist with USGS.

Hudnut recently told KPBS the fault zone is overdue for a magnitude 7.0 earthquake.

“It seems there’s a section of the fault near Anza that’s ready to go in a larger earthquake,” said Hudnut. “It is considered to be primed and ready.”

There were eight earthquakes of a magnitude 6.0 or higher along the San Jacinto Fault in the 20th Century. The last significant quake to strike the San Jacinto was a magnitude 5.4 temblor in July of 2010.

Another active fault in the region is the Rose Canyon Fault which runs through the city of San Diego.

“You could have a 6.4 magnitude just as the northern end of the same fault did in 1933 up in Long Beach,” SDSU Geologist Pat Abbott recently told KPBS.

“That could happen any time and it’s right inside the town. That would cause some widespread damage — Not like Japan, not even as bad as Northridge, but a significant earthquake with significant damage,” Abbott added.

Abbott said San Diego’s offshore faults are also capable of producing large quakes.

“Everyone of those islands you see out there — Coronado Island, San Clemente Island, Catalina Island — they’re all there because they’ve been lifted up by active faults. And those faults out there could also do things in the 6.5- to 7-point range,” he said. 

The San Andreas Fault, which starts east of San Diego County near the Salton Sea and runs to Northern California, forms the tectonic boundary between the Pacific Plate and the North American Plate. The movement of those plates is anticipated to cause a major 8.0-magnitude earthquake in Southern California

The big question is: When? A large rupture could happen at any moment or it could be 30 years from now, Thomas Rockwell, professor of Geological Sciences at San Diego State University, recently told KPBS.

“What we can say is, these faults are ripe. They really look like they can fail in the near future,” Rockwell warned.

The Great ShakeOut drill was first held in California in 2008. Since then, participation has spread around the globe. This year, Japan, Canada, Italy and Guam are joining in the drill.

Source: KPBS News –