Forecast: Big quake likely in Calif. By ALICIA CHANG, AP Science Writer
Mon Apr 14, 6:20 PM ET



LOS ANGELES - California faces an almost certain risk of being rocked by a strong earthquake by 2037, scientists said Monday in the first statewide temblor forecast.

New calculations reveal there is a 99.7 percent chance a magnitude 6.7 quake or larger will strike in the next 30 years. The odds of such an event are higher in Southern California than Northern California, 97 percent versus 93 percent.

"It basically guarantees it's going to happen," said Ned Field, a geophysicist with the U.S. Geological Survey in Pasadena and lead author of the report.

The 1994 Northridge earthquake under Los Angeles' San Fernando Valley was magnitude 6.7. It killed 72 people, injured more than 9,000 and caused $25 billion in damage in the metropolitan area.

The damage created by an earthquake depends greatly on where it hits. A 7.1 quake — much stronger than Northridge — hit the Mojave Desert in 1999 but caused only a few injuries and no deaths.

California is one of the world's most seismically active regions. More than 300 faults crisscross the state, which sits atop two of Earth's major tectonic plates, the Pacific and North American plates. About 10,000 quakes each year rattle Southern California alone, although most of them are too small to be felt.

The analysis is the first comprehensive effort by the USGS, Southern California Earthquake Center and California Geological Survey to calculate earthquake probabilities for the entire state using newly available data. Previous quake probabilities focused on specific regions and used various methodologies that made it difficult to compare.

For example, a 2003 report found the San Francisco Bay Area faced a 62 percent chance of being struck by a magnitude 6.7 quake by 2032. The new study increased the likelihood slightly to 63 percent by 2037. For the Los Angeles Basin, the probability is higher at 67 percent. There is no past comparison for the Los Angeles area.

Scientists still cannot predict exactly where in the state such a quake will occur or when. But they say the analysis should be a wake-up call for residents to prepare for a natural disaster in earthquake country.

Knowing the likelihood of a strong earthquake is the first step in allowing scientists to draw up hazard maps that show the potential severity of ground shaking in an area. The information can also help with updating building codes and emergency plans and setting earthquake insurance rates.

"A big earthquake can happen tomorrow or it can happen 10 years from now," said Tom Jordan, director of the earthquake center, which is headquartered at the University of Southern California.

Researchers also calculated the statewide probabilities for larger temblors over the same time period. Among their findings: There is a 94 percent chance of a magnitude 7 shock or larger; a 46 percent chance of a magnitude 7.5 and a 4.5 percent chance of a magnitude 8.

The odds are higher that a magnitude 7.5 quake will hit Southern California than Northern California — 37 percent versus 15 percent.

Of all the faults in the state, the southern San Andreas, which runs from Parkfield in central California southeast to the Salton Sea, appears most primed to break, scientists found. There is a 59 percent chance in the next three decades that a Northridge-size quake will occur on the fault compared to 21 percent for the northern section.

The northern San Andreas produced the 1906 San Francisco earthquake, but the southernmost segment has not popped in more than three centuries.

Scientists are also concerned about the Hayward and San Jacinto faults, which have a 31 percent chance of producing a Northridge-size temblor in the next 30 years. The Hayward fault runs through densely populated cities in the San Francisco Bay Area. The San Jacinto fault bisects the fast-growing city of San Bernardino east of Los Angeles.

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On the Net:

U.S. Geological Survey: http://www.usgs.gov

Southern California Earthquake Center: http://www.scec.org

California Geological Survey: http://www.conservation.ca.gov/cgs/

Well i have to say i bet it wont be That long...as a matter of fact,if i were to bet on it,i would say we will have a big quake here in california sometime in 2010.Maybe in August of 2010.Just a guess,that's all.Oh,and to be clear on this,i mean a REAL BIG earthquake...like 9.7...lasting for at least 6 min.Off the coast of Los Angeles.Any one else care to take a guess as to size and Location, duration and time please speak up.(i so love natuaral disasters)

I can't even imagine a 9.7 but I know years later there would be a legend about the lost city of Los Angeles

predictions like this make me laugh. they give a 31 year window for it to happen. i predict that a catastrophic hurricane will hit the eastern seaboard within the next 31 yrs also. when it happens, does that make me a genius or psychic??? not to mention, in 31 yrs. the one that came up with this prediction will be dead or forgotten, so if he's wrong - who cares???

Greetings;

According to the USGS Earthquake site map that shows the recent earthquakes by the hour, day and week- there have been alot of earthquakes not only in California up and down the coast, Reno, Nevada had a good size one with alot of aftershocks, the Las Vegas area had a few smaller ones along with other areas in Nevada, Utah, Alaska has alot of quakes on the mainland as well as her island chain, Hawaii-due to her volcanoes, the central US area had a good size one, Puerto Rico is having alot of them lately. The map is interesting for those who want to know where they are "popping" up at. Interesting.
The Yosemite area-where the supervolcano is located is only having small quakes-normal for that caldera which is building-but they are not looking for that to go off for quite a long time.

From all the quakes-it looks like the earth is on the move.


Raven2

They have been predicting a big one for California for some years now. Eventually they will be right. In the meantime, live your lives as usual. No sense to get worried about nothing you can prevent anyway. Am I correct??? So, let it rip and rip big. Might just put some sense into people in that state or decadence and self centered people there. A big change is healthy for a country don't you think so???