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Chilling video simulates a 7.8 quake

November 12, 2008 12:00:00 AM PST
They call Thursday's earthquake drill "The Great Southern California ShakeOut." Scientists painted a chilling picture of what a 7.8-magnitude earthquake would look like.There are signs all around Southern California of past earthquakes, like the mountains that surround the Los Angeles basin, produced by big earthquakes in the past.

Southern California is on the eve of "The Big One," the biggest-ever earthquake drill. Emergency responders, scientists and more than 5 million citizens who've signed up online will participate in what's called "The Great Southern California ShakeOut."

What's coming is a 7.8 earthquake centered near the Salton Sea. An earthquake that big would produce shaking 50 times stronger than the 1994 Northridge earthquake.

"We clearly understand, given the predictability and the magnitude of this earthquake, that public safety, the fire service, law enforcement, emergency medical services and government will be overwhelmed," said Chief Michael Freeman, L.A. County Fire Dept.

U.S. Geological Survey scientists have developed a video of the scenario. The red is the most violent shaking, exaggerated 1,000 times. Southern California is 150 years overdue for quake like this.

"Landslides would be starting when they are subjected to the strongest shaking. Now we can see the S-wave, which is very intense in this particular area as the rupture hits us. There's the S-wave. Now the rupture is coming through at approximately 64 seconds. There you can see the offset across the fault as one side moves relative to the other approximately 12 feet, offsetting I-15," said Brad Aagaard, USGS research geophysicist, as he described the earthquake animation.

The epicenter may be 150 miles away, but shaking from a great earthquake would be severe throughout the region, as demonstrated in animations showing how the shock waves hit Ontario, Orange County and central Los Angeles.

"You'll notice that there's black areas; those correspond to areas that are undergoing very intense shaking, so even after areas reach a peak intensity in the red, the black areas continue to show what areas are subjected to strong shaking, even after reaching their peak intensity," said Aagaard.

The challenge for average citizens, say the experts, is not just to ride out a big earthquake, but to be prepared to survive without outside help for days, even weeks. That means having fire extinguishers handy in your home or office; also, stocking up on food, medical supplies and lots of water.

Remember Hurricane Katrina? Officials here say "The Big One" would topple 1,500 buildings, start fires and kill and injure thousands.

"Part of the analysis we were actually trying to understand: what makes a natural disaster become a catastrophe? And we end up with a question: Well, it's going to depend on how much our social system can hold together," said Dr. Lucy Jones, USGS.

The drill will go on for three days, a not-so-subtle reminder of what's in Southern California's future.

 

More info: The Great Southern California ShakeOut

The Great Southern California ShakeOut is a week of special events featuring the largest earthquake drill in United States history, organized to inspire Southern Californians to get ready for big earthquakes, and to prevent disasters from becoming catastrophes. What we do now, before a big earthquake, will determine what our lives will be like after. The ShakeOut drill will occur in houses, businesses, and public spaces throughout southern California at 10 a.m. on November 13, 2008.

Free registration at www.ShakeOut.org/register will pledge an individual's or a group's participation in this important preparedness event. Participants will receive information on how to prepare for the inevitable major earthquake in the region and what actions to take during and after the shaking.


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