The "Big One" -- a 7.8 magnitude earthquake along the San Andreas Fault -- hit Southern California Thursday…. sort of.
An estimated 5.1 million people are participating in the Great Southern California ShakeOut earthquake drill, including more than 400,000 San Diegans. At 10 a.m., bells from Museum of Man's California tower signaled the start of the drill. Visitors were advised to drop and cover and staff from museums and park areas helped "evacuate" them.
Students at Deportola Middle School in Clairemont Mesa also dropped under their desks for cover as the simulated quake hit. Injured "victims" will be taken to a medical triage set up at UCSD Medical Center in Hillcrest. Other participants are staging full-scale exercises complete with search-and-rescue missions.
The effect such a quake would have on a three-story reinforced concrete structure was demonstrated at UCSD. The construction of the building is representative of buildings from the 1920s. The simulated quake caused the building to move back-and-forth for about 15 seconds, leaving behind some visible cracks.
The drill is the biggest, most inclusive ever staged to ready for earthquake preparedness and local governments, emergency responders, schools, hospitals, churches, businesses and residents doing their part.
California is the most seismically active state in the Lower 48. Earlier this year, the USGS calculated the state faces a 46 percent chance of being hit by a 7.5 or larger quake in the next 30 years with the epicenter likely in Southern California. Such a quake would cause 1,800 deaths and $200 billion in damage, researchers estimate.
For more information or to register for the dril visit "The Great Southern California ShakeOut."