By ALICIA CHANG
AP Science Writer
LOS ANGELES (AP) -- Southern Californians dropped to the ground, covered their heads and held on to the furniture Thursday for a mock "Big One" -- an earthquake drill billed as the largest in U.S. history and aimed at testing everyone from state leaders to students who donned fake blood to play victim.
Local television stations interrupted their regular programming to announce the drill and covered it as they would a major earthquake, though with continual reminders that the emergency wasn't real. Firefighters with chain saws and shovels broke through facades searching for mock victims, wading in some instances through blinding clouds of manufactured smoke.
Sirens blared at Bishop Alemany High School, a San Fernando Valley campus badly damaged by a 1971 temblor and destroyed by the 1994 Northridge earthquake.
Spanish teacher Fiorella Linares, who had been checking homework, ordered her approximately 20 students to "cover," and they dove under desks and grabbed onto the legs of chairs.
Some of the teens giggled and joked. "I'm dying," one shouted in mock horror.
"Don't laugh," Linares scolded. "You have to think about what if this really happened."
The exercise was based on a hypothetical magnitude-7.8 temblor rupturing the southern San Andreas Fault -- an event that scientists call the feared "Big One." Such a quake would cause 1,800 deaths and $200 billion in damage, researchers estimate.
Local governments, emergency responders, schools, hospitals, churches, businesses and residents were taking part. Organizers said some 5 million people had signed up to participate.
"We're trying to make it a communal event," U.S. Geological Survey seismologist Lucy Jones, who helped create the crisis scenario, said before the event.
The minimum participation calls for people to dive for safety. Firefighters and other emergency responders are staging full-scale exercises complete with search-and-rescue missions and medical triaging of people posing as casualty victims.
Shortly before the fake quake struck, Alemany students lined up to receive makeup that would turn them into simulated quake victims. Fire Department workers applied fake blood, makeup and wax to create gruesome injuries.
Patricia Esguerra, 17, sported purple cheeks and a simulated gash on her forehead.
"It feels nasty but it's for a good cause so I don't mind," said Esguerra, who lived through the devastating Northridge quake but remembers little about it.
The school's football field was turned into a triage center, with students arriving with different colored wristbands indicating the severity of their mock injuries.
"It's exciting. It's better to be prepared. At the same time, it's nerve-racking," said 17-year-old Emily Loren whose head was bandaged and who had an IV attached to her arm. Firefighters took her from the area by stretcher.
Gov. Arnold Schwarzenegger arrived at the school in the late morning to survey the situation. He thanked the federal government for funding the drill and praised the various agencies who cooperated.
"The locals, the state and the federal government came together very quickly, unlike what we have seen at (Hurricane) Katrina, when it was going the other way," Schwarzenegger said.
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.
Thursday's mock quake was in a section of the San Andreas that has not popped in more than three centuries and scientists fear stress buildup could unleash a big quake in the near future.
Under the scenario, the southern San Andreas suddenly awakens near the Mexican border, sending shock waves marching toward Los Angeles and eventually stopping in the high desert. The 200-mile rupture would leave a path of destruction. Shaking would last three minutes.
Despite the known seismic risks, California has never been as organized as Japan, which holds an annual quake drill to mark the 1923 Great Kanto earthquake, a magnitude-8.3 temblor in Tokyo that killed more than 140,000 people.
Interest in the statewide exercise was initially low, Jones said, but peaked after the state was jolted by a moderate quake this summer.
Though a far cry from the "Big One," the July magnitude-5.4 temblor centered in the hills east of Los Angeles was the strongest to rattle a populated area of Southern California since the 1994 Northridge disaster. After the shaking stopped, 400 new people signed up for the drill, Jones said.
If such a quake like the one in the drill hit, scientists say, sections of freeways would collapse, water and gas pipes would burst and certain high-rise buildings and older structures would fall.
As dire as the simulated quake seems, it's not the worst-case scenario, scientists say. The scenario, for instance, omits the presence of Santa Ana winds, which typically blow in the fall and have the ability to whip quake-sparked fires into infernos.
The drill coincides with an annual statewide preparedness event put on by the state. Besides rehearsing for natural disasters, the state in the past has responded to simulated terrorist attacks.
It's not all doom and gloom. Scientists plan to follow up the drill with a rally in downtown Los Angeles on Friday.
(Copyright 2008 by The Associated Press. All Rights Reserved.)