. . . I think . . . Guess I better get back to work and finish off today's tasks - and call it a day!
(Thank you) 8^)
Posted on 04/15/2004 6:30:31 PM PDT by BenLurkin
PALM SPRINGS - The San Andreas fault may be on the cusp of producing larger and more frequent earthquakes in a flurry of seismic activity that could rattle Southern California with a strong temblor every few decades or less, a geologist said Wednesday. A detailed analysis of two periods of past quake activity on a section of California's most notorious fault suggests a drawn-out period of little seismic activity may be coming to an end, said Ray Weldon, a University of Oregon geologist.
"Possibly we are at the point of switching from a period of time with a relative paucity of large and frequent earthquakes," Weldon said.
Weldon cautioned the switch could be decades away and that "flurry" is a relative term, since a cluster of quakes can strike over periods lasting 200 to 300 years. However, intervals as brief as 10 years have separated individual quakes in past clusters, he added.
Details were presented Wednesday at the annual meeting of the Seismological Society of America.
Digging into the San Andreas at Wrightwood about 60 miles northeast of downtown Los Angeles, Weldon and his colleagues found evidence of 30 quakes of magnitudes between 7.5 and 8.0 that had struck between 3000 and 1200 B.C. and A.D. 500 and the present.
An earthquake on the southern San Andreas of magnitude-7.5 or larger could kills thousands of people in the greater Los Angeles area and cause damage estimated in the tens of billions of dollars, experts have said.
On average, quakes of that size have struck Wrightwood at roughly 100-year intervals, although the lulls between tremors lasted as little as 10 years and as long as 224 years.
When viewed in series, the quakes appear to have struck in flurries, followed by periods of relative quiet.
The southern portion of the fault last ruptured in 1857. Current levels of strain measured on the San Andreas are at their highest in 1,500 years and suggest the fault is due to begin releasing that pent-up energy as a large earthquake or quakes, Weldon said.
Other seismologists said that the apparent clustering of quakes could be random and warned against inferring they consistently strike in recognizable clusters.
"It's human to look at these things and see patterns," said Geological Survey of Canada seismologist John Adams.
Taking a short break from another ten hour work day . . . and maybe I'm tired . . . but can someone please explain this line to me?
Bush knew!
Two periods of time:
3000 BC - 1200 BC.
500 AD - 2004 AD.
during that collective time span, 30 quakes 7.5-8.0 occurred.
I think.
Thanks!
Oops . . . forget the part about nothing big happening between 1200BC and 500AD. On second reading he seems to be saying there were 30 big quakes during the 3300 years he studied. But he isn't making any claim at all about the 1700 years between those two periods.
That reminds me of an old buddy. Some would say he was a good photographer, but I contended he was a boy with a good toy and a lot of time to kill. If you have every expensive gadget and take a zillion shots of the same subject using incremental settings, you're bound to get at least one good shot. Does that make you a good photographer? I understand Ansel Adams could shoot a masterpiece with only one exposure - that's skill.
Sorry for the tangent. I'm finally starting to come down from my April-15th anger craze.
. . . I think . . . Guess I better get back to work and finish off today's tasks - and call it a day!
(Thank you) 8^)
I was born and raised here (L.A.), 37 years now,what's the big deal when you're prepared, literally and figuratively,hmmm? sheesh..........
Worry about the millions that are NOT prepared and in a crisis will see fit to try and appropriate your preparations claiming 'need' for it.
The problem is you haven't experienced any REAL quakes. Don't kid yourself. Northridge, Sylmar were decent, strong quakes, but not huge by any measure, and only a shadow of what is possible. You have no idea what you're up against, mark my words.
Geology is measured in millions of years. 37 years is an irrelevant eye-blink.
Southern California has had an unusually low amount of quake activity in the last 50 years or so compared to what's "normal"..unfortunately, that's when the population exploded.
Huh?
The LESS solid ground your on, the worse off you are in a quake, not better off. Ideally you'd be on solid rock. Mud is the worst, but sand likely isn't much better.
Sorry to run out on the conversation like that. I got a rather imperative reminder that dinner was ready and didn't have time to hit even one more key. :-)
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