California Quake

USGS ^

[Drago]

Just felt a quake here in the Fresno area...

[MineralMan]

Here's another graphic, which shows the relative motions of the west coast of the US. Note that the boundary between the Pacific Plate and the North American plate is not a subduction area. The San Andreas Fault is a transform fault, meaning that the boundary of the two plates is a zone where one plate is sliding against the other. North of Mendocino, you find the subduction of the Juan de Fuca plate, which leads to the formation of the Cascades, extending down clear to Mt. Lassen in CA. The Los Angeles area is actually atop the Pacific Plate, while the rest of CA is on the North American plate. For a very, very long time, the Pacific Plate has been moving northwards, which is why CA can't fall off the map. I hope this helps.

[Ptarmigan]

That's a really strong earthquake.

[Zevonismymuse]

We never stop shaking in California.

I was in the second story office of one of Michael Jackson's attorneys in downtown Santa Barbara. When the quake stopped I heard the lawyer ask the support staff,"Was that Randy Jackson calling back?" Everyone is the office started laughing.

Thankfully, I was not billed extra for the earthquake.

[Awestruck]

LOL! get out of my head!! ( I just used that quote yesterday)

[ravinson]

No such thing as earthquake weather, missyme.

How do you know MineralMan? Just because no one has proven a relationship between weather and earthquakes doesn't make it an impossibility. No one seems to have carefully studied the relationship between earthquakes and tides/moon phases before Jim Berkland did, and he seems to be on to something. (Note that the Parkland quake has occurred during a full moon at high tide.)

[Arthalion]

The "shallow" hypocentral focus has been revosed to nearly 8km.

Yep. I wonder how they missed by so much. A 6.0 at 7.9km is still capable of doing a lot of damage, but far less than at 1km (different kind of shaking). This is good news :)

[Veto!]

The Alaska quake was a 4.8, according to an Alaska Earthquake site and located far from the mainland, 43 miles sE of Adak, the star on this map:

[GOP_1900AD]

There's a reason it's called the Ring of Fire. [Images of Johnny Cash and Stan Ridgway now floating in my head.... ;) ]

[GOP_1900AD]

The plate being subducted beneath the North American Plate along the trench that runs from Humboldt County CA up to the Strait of Juan De Fuca is a rather small one. There is a minor spreading center a few hundred miles west of that trench. As the small plate subducts, volcanos in the Cascades happen. The Cascades run from Mt. Lassen, in far northern CA up to Mt. Baker, in N. WA (from about 41 N. lat up to about 49 N. lat.). The San Andreas and related faults run from the northern tip of the Gulf of CA up to the point where the trench and the spreading center join up in what is known as a triple junction, off the Humboldt Coast. It has a right lateral "strike slip" motion - e.g. the plates are grinding past each other in slight compression but there is little vertical or overiding motion. The SAF runs roughly NNW - SSW but takes a major jog between just north of Palm Springs and just north of Ventura. It also takes a smaller jog between Hollister and Woodside. As a result of the two jogs there are normal and thrust faults picking up some of the local strong compressive motion. Also, to accomodate the bends, there are Left lateral faults at ~ 30 / 60 degree angles to the SAF. The stuff going on in the Mojave Desert and east of the Sierra Nevada (also in Nevada, Idaho, Montana, Utah) in terms of geothermal output and minor volcanism have nothing directly to do with the SAF. Speaking of triple junctions there is a theory that there is a failed triple junction in the Gulf of CA the failed third arm of which accounts for this intra continental volcanism. Either that or the North American continent is slowly getting torn apart and a new ocean will form between the Gulf of CA and the Arctic at some point.

[GOP_1900AD]

Nah, they just retrofitted all the fermentation tanks in the wineries! ;) LOL .....

[GOP_1900AD]

Nice graphic. BTW,I once took a course from Dr. Tanya Atwater. The source... well at least one of the sources .... ;)

[GOP_1900AD]

Well. let's see. In central CA today, there was a major on shore push of the marine layer, breezy, with coastal drizzle. Not exactly the warm and still conditions of so called earthquake weather. Someone mentioned they had "earthquake weather" in San Diego - only problem is, San Diego is over 300 miles south of the area affected by this quake.

[ravinson]

In central CA today, there was a major on shore push of the marine layer, breezy, with coastal drizzle. Not exactly the warm and still conditions of so called earthquake weather....

According to The Weather Channel, it is 70 degrees and sunny in Paso Robles right now with winds less than 10 mph. I'm not asserting that there is any such thing as "earthquake weather", but I certainly wouldn't rule out that possibility.

[Orion78]

Just spoke to relatives near the epicenter, and they said it was more of a rolling earthquake rather than a sharp, violent one like the December San Simeon Quake.

[Yaelle]

Thanks for the ping -- I was out and about and had no idea that there even was an earthquake.

[edchambers]

Enough already! I felt here in Atascadero,SO WHAT,nothing broke, nothing even fell over, no one died, and for this all the local Radio stations preempted Rush and Hannity so they could take SIX HOURS of callers going "no I'm fine,nothing broke,that was more of a roller than a shaker don't ya think?"AHHH!I felt it in Cambria,Morro Bay,San Luis,Paso Robles,Templeton,no we're fine.AHH!,AHHH!THIS IS CALIFORNIA WE HAVE EARTHQUAKES HERE GET OVER IT.

sorry, rant mode off no I'm fine really.

P.S. no I didn't read though all 400 something post to make sure everyone is OK

[capitan_refugio]

The initial figures are probably generated by instruments near the epicenter. If you are right on top of the epicenter, there is no telling how deep the hypocenter really is.

The best hypocentral data are developed form observing several sets of data.

[tubebender]

In 1700 the area of the Triple Junction up into British Columbia ruptured and set off a 9+ R that did much to alter the landscape from Eureka Ca north. They were able to document the event to the minute by studying data in Japan of the resulting Tsunami. I have seen a core sample from Crescent City showing a one inch layer of setiment from the Anchorage quake and tsunami of 64. The same core sample shows a four inch layer from the 1700 event. Further studies show a 9+ event every 300 years in this area.

[7.62 x 51mm]

Didn't feel it here in York, PA. Just 3.4" of rain so far, from TS Jeanne and 35-40 mph winds. You all take care out there in The Peoples' Republik of Kalifornikate!

[HitmanLV]

One of my fave Mama Cass songs.