Posted on 10/01/2016 7:35:13 PM PDT by nickcarraway
The probability of a magnitude-7 earthquake in Southern California briefly increased as much as 50-fold earlier this week, but has since been dropping back to normal, according to the U.S. Geological Survey and other quake experts.
What changed things was a cluster of small quakes that began Monday near the southern end of the San Andreas fault. Seismologists believe that quake activity on one fault can lead to increased stresses on another, said Rob Graves, research seismologist based in the Pasadena USGS office.
The cluster was epicentered beneath the Salton Sea, near Bombay Beach, within a handful of miles of the San Andreas. Some 150 quakes were detected within a 24 hour period, the largest only a magnitude 4.3, before the swarm began to taper, Graves said The southern segment of the San Andreas Fault, California's longest and therefore capable of the largest quakes, has not unleashed a major quake in more than 300 years. One scenario developed in 2008 for the "big one" calculates a magnitude-7.8 quake beginning near the Salton Sea and spreading northwest along the fault, claiming 1,800 lives and causing The probability of a major quake on the San Andreas during an one week has been put at 0.02 percent. As a result of the Salton Sea Cluster, the probability for this current week, beginning Tuesday, was deemed to have increased to, at minimum 0.04 percent, and at the other end to as much as 1.0 percent, 50 times greater than usual.
On Tuesday, the Governor's Office of Emergency Services (OES) asked the California Earthquake Prediction Evaluation Council to evaluate the Salton Sea clusters. The Council found an increased likelihood over the next week of a quake larger than magnitude 4.3, according to an OES statement. Later that afternoon, OES convened a conference call with emergency managers in eight Southern California counties to "ensure that local emergency plans and preparedness education remains a priority. Since Tuesday, the frequency of quakes in the cluster has dropped rapidly, lowering the probability of triggering other quake activity.
"Within two weeks, it will probably be back to the background level," said Graves, "assuming we don't see any additional activity in the swarm."
In the past 15 years, two previous clusters had been detected in the same area of the Salton Sea, in 2001 and 2009. Those clusters included quakes of magnitude 5, but neither was followed by anything larger on the San Andreas, Graves said.
What did I do to offend you?
I’ve got family and friends in CA.
LA is probably 50-60 miles away at it’s closest from the fault.
Where did that image originate. Just curious.
Just drove through your county this morning. Just got home an hour ago (Florida). I didn’t feel any tremors though while there
2012 movie
BTW, there is no tectonic scenario where any significant portion of California “falls into the sea”.
The worst, or most interesting possibility depending on where you are, (I’m a geologist) would be if either the Central Valley shook long and hard enough to cause a significant sediment consolidation in areas and they back filled with sea water until equilibrium was reestablished OR activity raised the area of the golden gate enough that it restricted the outflow of water.
Another item of awesome coolness would be if a volcano was going to form there like Paricutin.
Another item of awesome coolness would be if a volcano was going to form there like Paricutin.There's always the La Brea Tar Pits.
__Volcano(1).jpg)
Bill Murray said it in;
CADDY SHACK
So now we know what geologists do at 1 AM, sit up all night and wonder if there is a doG:) Will you take calls at 3 AM?
What is you worst case awesome coolness scenario for the Cascadia Fault.
I haven’t really thought of that since I’m not in the prime area and probably couldn’t get there in time. My mom was pregnant with me at Ft. Lewis while dad was stationed there during the 65 Puget Sound earthquake, she’d related I was born in one, which would have had to have been an unrecorded aftershock as I came out a few months later. She was at the clinic when the main one went though and got to waddle around the hallway dodging carts and other stuff.
My running joke is the most seimically stable area on earth appears to be wherever I’m located. Nothing in VA for near 20 years and then after I’ve moved out here they have a 5.8...
If you live in CA, stock up on some bottled water and camping meals, I’m driving to the Field Target National Match in Michigan next week...
Thanks. Good luck at the match.
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