The threat of future earthquakes across the Bay Area, from the U.S. Geological Survey. Credit: USGS
Posted on 05/20/2014 2:06:16 PM PDT by BenLurkin
California's San Francisco Bay Area grew into a metropolis during the eerily quiet earthquake gap following its devastating 1906 temblor. Scientists predict a 63 percent chance of another big quake before 2032, but when the shaking starts, it may not be a single "Big One" as in 1906, according to a new study.
Instead, the Bay Area could face a cluster of deadly earthquakes that deliver a series of rapid punches, researchers report today (May 19) in the Bulletin of the Seismological Society of America.
....
Between 1690 and 1776, the Bay Area's most dangerous faults unleashed a series of earthquakes between magnitude 6.6 and 7.8, Schwartz and his co-authors report. (The 1906 San Francisco quake was probably a magnitude 7.9, using modern estimates.) These include the Hayward fault, the San Andreas Fault, the northern Calaveras fault, the Rodgers Creek fault and the San Gregorio fault.
An earthquake lull followed this quake cluster...Then the 1906 earthquake struck, and a life free from big earthquakes returned again.
Schwartz (and the USGS) thinks it won't be long before San Francisco starts to shake again. The big question is whether it will be the feared "Big One" or a cluster of earthquakes, and which would be worst.
"We haven't had to face a series of relatively closely timed earthquakes in a modern, urban city," Schwartz said. "It would be bad news."
However, the discovery doesn't immediately change the USGS official earthquake forecast for the Bay Area, which projects a 62 percent chance of a magnitude-6.7 earthquake by 2032, Schwartz said.
...
(Excerpt) Read more at livescience.com ...
ping
chance of earthquake?
it either happens or it doesn’t.
50-50 the way i see it.
I recently read several articles which said that geologists fear that the greatest danger is from smaller, as yet, unidentified and unmapped faults..they could go off on their own, or be the trigger for a much bigger one..
I tend to agree, and I give earth scientists a lot of credit on the high probability to malarkey scale.
Seismology, though primarily statistical, is yet well grounded in physics, and it’s very difficult to purposely advance a false argument into the scientific method of physics or mathematics.
Now, in climatology OTOH....
The account overlooks a significant quake in Hayward in 1868.
I can see the Rodgers Creek fault from my house.
I think it would depend on the local tectonics which, in CA, vary widely, and have displayed remarkably diverse histories, many even just a few kilometers apart.
Slightly off topic..but I thought that the general consensus among geologists was that the Cascadia fault...off the coast of Washington and Oregon,,up past Vancouver..was far more likely to go soon, causing a big quake and a tsunami. Tey also feel that if the Cascadia fault trips all the way down the coast..it could set off the San Andreas..
I have heard that possibility as well. Imagine it...a ‘Full Rip 9.0’ all the way from Vancouver Island through Northern Cali, which damages Vancouver, Seattle, and Portland....and THEN the San Andreas lets go and does SF.
That, FRiend, is a true ‘nightmare scenario’.
let me guess, this is all due to made made climate changes ?
The shorter and smaller one makes the time frame for prediction, the closer to -0- the probability. For example, the probability of a big earthquake happening in between 5:05 and 5:10 pm on 20 May 2014, that probability is effectively zero, although technically not zero.
“let me guess, this is all due to made made climate changes ?”
Nope. This will be cause by George Bush and Richard Nixon though it is possible that Ronald Regan will also receive some of the blame. This is because both Nixon and Regan were from California and Bush was just evil.
Those three are the fount of all evil according to the US political left
Having lived most of my life in, or near Memphis, I was always aware of the New Madrid fault that created the massive quake that was felt all the way to the east coast. If it goes off again, it could be catastrophic for much of the US.
Now that I am living in the Philippines, I am well aware of earthquakes, having experienced an 8+ quake this year, and a 6.3 just last week. Every morning I review the daily activity on the national earthquake site,
http://www.phivolcs.dost.gov.ph/html/update_SOEPD/EQLatest.html
They show 10 quakes for yesterday alone.
Tsunami, definitely. But muddling it over a bit, the Cascadia is a subduction zone, while the San Andreas is a transform system. Despite those who say that all change is global, its hard given really big events to understand how they actually impact Earth’s structure overall.
I seem to recall an ~9.0 along the west coast of South America some years ago. It would have done a lot of damage, but it was so deep, I think >600 miles, that those on the surface barely felt it, but certain aspects of those seismic waves reflected and refracted thorough the earth for a long time.
As for that tsunami, we’re about 15 miles inland at around 450 feet, so I hope it ain’t too big.
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