San Andreas Fault
Posted on 01/09/2010 4:44:46 PM PST by VRWCTexan
URGENT -- MAGNITUDE 6.5 QUAKE HITS WEST OF FERNDALE IN NORTHERN CALIFORNIA
I remember that. Wasn’t there... was playing chess with my brother when it came across the news. I remember saying it looked like a bridge collapsed, top roadway onto the bottom about a minute before the newscaster said it.
San Andreas Fault
Surface rupture ?
There are no islands offshore of the California coast at the MTJ. Thus, earthquake location accuracy rapidly degrades as the quakes occur farther from shore because of the one-sided seismic network station geometry. Depths of quakes west of 124º40'W (approximately 50km offshore) are unreliable except for the larger (M>3.5) quakes for which moment tensor inversions can resolve the depth. Likewise, the location accuracy in the direction perpendicular to the coast degrades with distance offshore. The addition of Ocean Bottom Seismometers (OBS) would greatly improve the ability of the NCSN and BSL to understand the seismotectonics of the MTJ following significant quakes. Improved understanding of the rupture mechanics of a subduction zone quake would enable seismologists and hydrodynamicists to more realistically forecast onshore shaking levels and tsunamis. OBS recordings with extended dynamic range and frequency response could possibly reveal the generation mechanics of slow, tsunami quakes. Near-field recordings of offshore earthquakes would greatly improve depth estimates of aftershock sequences and confirm stress transfer models in a region with significant seismic risk.
There are several earthquake scenarios that could warrant a mobilization of the OBS systems. a) M>6.5 quake on the Gorda-North America subduction zone (”G-NA” polygon), b) M>6.5 quake on the Mendocino fault east of longitude 126ºW (”G-P” polygon), and c) M>6 quake on the SAF north of Point Arena (”P-NA” polygon). Deployments within 3 days of such an event are highly desirable due to the unpredictable aftershock decay rate.
There are several harbors along the coast that would provide a base where vessels could be hired to deploy the instruments. Humboldt Bay (Arcata and Eureka) provides the best facilities in the vicinity of the MTJ. There are harbor facilities north of Humboldt Bay at Trinidad and Crescent City. The principal harbors south of the MTJ, which would be more suitable for responding to quakes on the offshore section of the SAF, are at Shelter Cove and Fort Bragg.”
Sounds like your source is asking for more (tax-payer) more of your tax-payer money for his Ocean Bottom Seismographs.
Look at link in post 50.
The Humboldt Bay area was rocked by a nice-sized earthquake at about 4:45 this afternoon. Preliminary reports put it at 6.5 on the Richter scale. Epicenter was about 24 miles west of Humboldt Hill. Power is out at least as far as Blue Lake, but it’s on in parts of Eureka
http://humboldtherald.wordpress.com/2010/01/09/earthquake-2/
Whoa! This is series! Looks like those sea lions were onto something when they hit the road for Oregon........
That doesn’t sound right. Most of Eureka is not all that low-lying.
It’s the Samoa (Calif.) part that would be under tsunami threat, if this had been a bigger quake.
Well, Thank You!! Looks interesting. I’m genning it up here in a second.
So....in Fortuna? I grew up down there.
Urgent - Earthquakes are common in California and tsunamis don't usually hit the coast of California after earthquakes........
In other news, its cold in Michigan.......
Ah. Way up north in the Mendocino fault. Tidal wave activity?
Just caught my eye on twitter - supposedly by someone on the scene and listening to local radio - cannot vouch for accuracy
We felt two good shakes this week in our office in Sunnyvale (Silicon Valley). Biggest was 4.5 or so on the Hayward fault. Didn’t feel the Ferndale shaker.
lol...wait. I’m thinking east. A 6.5 off the coast isn’t that bad.
Thanks Strategerist, I wish the USGS and the emergency services here where I am would be as specific as you. I’m on the south/central Oregon coast straight in from the subduction zone in an official “tsunami danger area”.
After seeing this on FR, I called 911, this would be about 20 minutes after the quake, and they said, “What earthquake?” I told them to check with USGS and take a look online. We’ve been taxed to put in ridiculous 1950’s technology warning sirens, like air-raid sirens. But when the people in charge are clueless, no one will sound the siren.
Problem with Oregon, especially the coast, is almost everybody’s on pot, so hard to get good response in an emergency. Thank heavens for FR and folks like you.
The Obamination says, "It's all San Andreas fault!"
Thanks - do you suppose this might trigger a bigger one elsewhere in CA?
You are right. It is TOTALLY AWESOME!!!! (and so darn fast)
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