Tuesday, April 27, 2010

[Geology2] The Big One: Earthquake Facts, Theories And Predictions

San Diego News

The Big One: Earthquake Facts, Theories And Predictions

Experts warn San Diegans to prepare for a hometown shaker
By Dave Good
Posted on Tue, Apr 27th, 2010
Last updated Tue, Apr 27th, 2010

They have all been Big Ones with ruinous consequences. And, they have been hitting populated areas of the world with far too much regularity. In recent weeks, earthquakes have been headline news in Haiti, then Chile, followed by China and Japan.

SDSU's Dr. Kim Olsen: A Big One is overdue.

Courtesy photo

On Easter Sunday, the action got closer to home when a 7.2 earthquake rocked Mexicali and rumbled its way through living rooms and office buildings from San Diego to Los Angeles. The quake left two dead in Baja and did about one million dollars' worth of damage to the border town, but the quake's effects here were minimal.

San Diego dodged a bullet that day, but as tremors and aftershocks rattled nerves in the days to follow, the question remained: are we due for a major earthquake here?

The answer is: yes.

"San Diegans should prepare," says Kim Olsen. "The Big One is coming." Olsen is a seismologist and a professor in the Department of Geological Sciences at San Diego State University. He and other seismologists are certain that San Diego is long overdue for a seismic shaker of large proportions.

When, and how big? Olsen says that the best science can do at present is to assign probabilities.

"In Southern California in the next 30 years," he says, "there is a 97 percent probability that we will get a magnitude 6.7 or smaller earthquake."

The relatively close San Andreas fault has been building up stresses for years that, he says,have not been released in the form of an earthquake since the 1600s. And while the San Andreas fault is overdue for a major event, Olsen says that there are a number of faults that are much closer to home that are capable of generating a 6.7 or even a magnitude seven earthquake.

The Uniform California Earthquake Rupture Forecast, Version Two says that California is veined with some of the most active earthquake faults in the United States.

"And we have the Rose Canyon fault," Olsen says, "that is capable of a magnitude seven and that runs pretty much through downtown and along the I-5 freeway up to La Jolla."

Researchers such as Debi Kilb of the Scripps Institution of Oceanography say that neither global warming nor planetary instability have anything to do with the recent spate of earthquakes. And, she says that there are no more earthquakes occurring now than at any other time. "The difference," she says, "is that they are happening in populated areas instead of out at sea or in the middle of the desert."

Earthquakes actually take place with disquieting frequency all over the globe. The US Geological Survey posts seven-day records of all of the world's earthquakes that measure 2.5 or larger. A quick perusal of their data lends the impression that quakes are in fairly constant supply on any given day.

But some see earthquakes as being more than just natural phenomenon.

In Lompoc, Bible prophecy teacher Frank Di Mora, author of The Last Chronicles of Planet Earth began a recent blog postwith this headline: "Listen to Jesus' warnings. Another major earthquake in China."

Some activists lay the blame on global warming. And then, there are the 2012 theorists. According to that line of reasoning, cataclysmic events will take place on December 12, 2012, supposedly the end of a 5,125 year-long cycle on the Mayan calendar.

But for earthquake victims in Mexicali, China, Chile, and Haiti, 2012 doesn't matter. Their world has already come to an end.

But anyone can prepare for a Big One. "Get your act together, "says Olsen, "and prepare yourself."

The first priority on the earthquake ready list is water, says UCSD Structural Engineering Professor Jose Restrepo, who spent time on the ground in Chile after their 8.8 shaker on February 27.

"Water is the most vital element. It is not likely that water service will be restored for the first several days." The rule of thumb for stockpiling, he says, is three gallons per person per day.

Experts also recommend keeping cash or traveler's checks on hand in case of bank closures, extra food enough for humans as well as for pets, tools, flashlights, waterproof matches, toilet paper and hand sanitizer, a first aid kit, extra clothing and bedding, and documents such as insurance policies and deeds, passports, bank and credit account information, and family records. And, they recommend that all computer data be backed up.

For more information on how to prepare for an earthquake, visit the Red Cross store or their Web site.


(Gars O'Higgins Station penguins)
(Twilight Saga commentary)
(Coming soon---Volcano Watch!)



Your email settings: Individual Email|Traditional
Change settings via the Web (Yahoo! ID required)
Change settings via email: Switch delivery to Daily Digest | Switch to Fully Featured
Visit Your Group | Yahoo! Groups Terms of Use | Unsubscribe


No comments:

Post a Comment