Posted on 09/09/2011 12:56:20 PM PDT by dragnet2
Earthquake
(Excerpt) Read more at foxnews.com ...
Udub seismologists on local news reporting this as a strike-skip type quake (like the San Andreas fault type) and as such IS NOT the big one!!!
Ny bad, very dark in my living room now, sb strike-slip...
LOL...i think we knew what ya were going for!
As for the pro...I very much agree.
Quakes in the Eastern US are felt over a much larger geographic area than West coast quakes because of the geology. When the New Madrid let loose, that was felt in Maine too. New Madrid is in Missouri.
Exactly right....solid cold bedrock as opposed to fractured heated in the west carry’s the shockwave much more efficiently.
I watch the maps (USGS) and the charts just about everyday and honestly I don’t think there is ANY indication that it’s ready to go soon.
If we were seeing half a dozen (or even 3 or 4) magnitude 4.5’s out there near the fault every week, then I’d say maybe we should be sweatin bricks.
But it’s just not there.
Historically, I don’t know. Much of the info about quakes here comes from core samples taken in the lakes and bays, and particularly with core samples taken from deep canyons offshore.
The reason is all quakes that are starting to get up there in terms of size, say 7.0 or larger, cause sediments to fall into these deep-water canyons from the sides near the top, and these sediment layers are easily distinguishable from normal ocean deposits.
But I don’t think it can be analyzed in enough detail to show what happened before the 1699 event.
But the 1699 event is there! And most, if not all, of the subduction events have signatures!
I seem to recall the average time between events as being 525 years or so...
Something like that.
Of course we know that the main quake was a severe subduction zone thrust event on the North American plate.
Anyone on Whidbey Island feel it?
Way north of Seattle.
Well, if we look at the known subduction zones around the world we might be able to get a clue about what to expect in Cascadia before/after a large event.
Japan - hundreds, if not thousands of micro quakes offshore there every day.
Indonesia - Same deal. Probably hardly a day goes by without a 4 or 5 in Indonesia somewhere
Chile - not so many microquakes, but you do see LOTS of 4’, 5’s, 6’s, and 7’s along a stretch of about 500 miles around Concepcion - site of the 1960 9.5+ subduction event, the largest quake ever recorded in history...
Kamchatka - What U see is what U get - this is a hodgepodge of large and micro quakes of all sorts. Not a day goes by that we don’t see a large quake in that region.
Compared to these regions, Cascadia is in a coma!!!
And I overlooked putting Alaska and the Aleutians on the list!
“I don’t want to live anyplace now where homo marriage is legal and Christians are persecuted for their beliefs.”
Are you talking about the local area around Victoria, or British Columbia as a whole?
>> “My wife was raised in Everett.” <<
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A suburb of Boeing... :o)
Here is to hoping that this relieves some stress within the Cascadia Fault. That big Biotch has been bound up FAR too long and THAT is a scary thing. VERY scary.
Which can be good or bad depending on where that increased stress on cascadia and where it increased it.....
My wifes’ grandfather helped build that plant and one of her cousins still works there.
>> “Lived in Modesto,CA in 1989 when the World Series earthquake hit,shook every rollup door in the warehouse,thought a truckdriver had run his 18 wheeler into the building,scared the heck out of me.” <<
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That is a shakey area. I was near there the day of the Watsonville quake, doing a boundary survey on the Maes ranch, and the quake shook down all of my setups, and we had to spend a couple of hours re-leveling all of them. It just shook us senseless.
Aftershocks from main quakes can last 100yrs or more....it’s a tough thing to figure out. Just pointing out that this has some earmarks of a forequake...a strike-slip that was of it’s own bearing would normally have aftershocks...but not always.
The Pacific Northwest is known for it’s microquakes and have recently spent thousands on new recording devices to measure them...their relationship is not known as being more due to volcanic activity or their closeness to the Juan de Fuca.
Like I said...I am just pointing out that this has a real possibility of being a door knocker. take it for what it’s worth.
>> “Nothing here in Anacortes. <<
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Good thing. Fractured oil refineries are not too cool.
The data and evidence show 13 great events in the last 6000 years or so, amounting to an average 430 years or so between events.
And it’s not just sediment data, they have tree ring data from buried timbers.
So even if you go by the average, we still have another 130 years or so, whether the average holds or not, there is NO indication that Cascadia is anywheres near going.
The 1699-1700 event happened after a fairly long duration from the previous one. Guesstimats say the one before 1700 was about 900 AD. so it was WAY over the average when 1700 happened. It’s probably quite safe to say that if you WANT to be around during a big quake, you missed the boat, because the 1700 event was a killer!
It was probably the North American counterpart of the 1960 Chile quake.
Wouldn’t surprise me if there was so much movement and stress relief during the 1700 event that is is quite a bit longer than average before the next event.
If we started seeing a LARGE increase in the micro-quakes, or a medium increase in events like the Nisqually quake, I might get shook up! (The Nisqually quake was very, very special!)
Until then, I’m way more worried about a 130 foot Doug fir falling on my place during a windstorm... or maybe a bear in my backyard! (SOMETHIN HUGE was on my compost pile last night, scared the BJeses out of me!!!)
Are you a geologist? Or a Seismologist? I find all this stuff fascinating because one day I will be involved in creating mitigations for events like that.
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