Posted on 06/21/2006 10:33:10 AM PDT by 300magnum
The southern end of the San Andreas fault near Los Angeles, which has been still for more than two centuries, is under immense stress and could produce a massive earthquake at any moment, a scientist said on Wednesday.
Yuri Fialko, of the Scripps Institution of Oceanography at La Jolla, California, said that given average annual movement rates in other areas of the fault, there could be enough pent-up energy in the southern end to trigger a cataclysmic jolt of up to 10 metres (32 ft).
"The observed strain rates confirm that the southern section of the San Andreas fault may be approaching the end of the interseismic phase of the earthquake cycle," he wrote in the science journal Nature.
A sudden lateral movement of 7 to 10 metres would be among the largest ever recorded.
According to the U.S. Geological Survey (USGS), the earthquake that destroyed San Francisco in 1906 was produced by a sudden movement of the northern end of the fault of up to 21 ft.
Fialko said there had been no recorded movement at the southern end of the fault -- the 800-mile long geological meeting point of the Pacific and the North American tectonic plates -- since the dawn of European settlement in the area.
He said this lack of movement for 250 years correlated with the predicted gaps between major earthquakes at the southern end of the fault of between 200 and 300 years.
Elsewhere on the fault, there were average slippage rates up to a couple of centimeters a year that prevented the build-up of explosive pressure deep underground.
When these became blocked and then suddenly broke free they produced tremors or earthquakes of varying intensity depending on the movement that had taken place before and the duration of the blockage.
USGS says the most recent major earthquakes in the northern and central zones of the San Andreas fault were in 1857 and 1906.
Fialko said there were three possible explanations for the lack of observed movement in the southern section -- creepage under the surface that had no external manifestation, that it simply might not move as much as the rest or a major blockage.
"Except for the first possibility above, the continued quiescence increases the likelihood of a future event," he wrote.
Making calculations based on a wide range of land and satellite observations, he discounted the idea of creepage and warned of impending disaster.
"Regardless of fault geometry and mechanical properties of the ambient crust, results presented in this study lend support to intermediate-term forecasts of a high probability of major earthquakes on the southern SAF system," Fialko said.
"Why isn't FEMA there already?"
Are you crazy? That could be dangerous. Better to wait 24 hrs. to let things calm down and then give a news conference.
One morning it won't be there and then you'll know............
Sorry... transponder code for "highjack".
Yet another reason for the sky-high real estate prices in So Cal...
/sarc
I believe he mentioned if everyone in LA would move to the east side of the fault then earth would once again be in balance. That may be inconvenient but it is the truth.
sarc/off
In a geologic "moment", perhaps, which could mean anywhere from 11:00AM today until 100,000 years in the future. EVERYONE !!!! INTO THE SEA !!!!
Should I postpone my annual three weeks to San Diego and Santa Barbara county? What to do?
The proverbial ticking timebomb...
Just so I understand this correctly...
The faults that are currently in Los Angeles County are off-shoots (or separate faults) of the San Andreas fault?
For example, the Northridge quake (was it in '93 or '94?) could have been from an off-shoot fault of the San Andreas fault - or from its own separate fault?
AOK, Gotcha...........
Yes, and increase gas prices $5 a barrel on this news.
Yeah, heaven forbid we let the local authorities handle things, and let locals pay for rebuilding.
What a nice way to clean the Gene pool...........
Why?
Didn't you hear?
Everything East of the fault will break off and fall into the Atlantic.
Why does Reuters switch from "metres" to "feet" mid-article...just to confuse things?
Earthquake Ping List. Please send a Freepmail if you want to be added to
or removed from this list.
"The southern end of the San Andreas fault ...... is under immense stress"
I recommend a long relaxing vacation, with maybe some massage therapy...
Something like 200 quakes a week.
I like the " did you feel it" section and always fill it out when we feel one in my area.
How long would it take to restore flow? Would a front-end loader and a bulldozer get things fixed up in an hour?
Disclaimer: Opinions posted on Free Republic are those of the individual posters and do not necessarily represent the opinion of Free Republic or its management. All materials posted herein are protected by copyright law and the exemption for fair use of copyrighted works.