7.7 Quake Just Hit SE Alaska High on the Cascadia Subduction Zone

reply to post by JustMike


Terrific explanation, Mike.

I wish I had waited to post the above, lol. You are our Bill Clinton, "Explainer-in-Chief", lol.

reply to post by Rockbeard


Nice to see a fellow Sitkan on here, I thought I was the only one. We still have a house on Baranoff I. and three years ago when we purchased a Earthquake rider on our insurance policy our agent laughed at us. He asked if we knew something they didn't because we were about the only ones he knew of that had Earthquake Insurance. Who's laughing now Carl? Anyway Rockbeard, I'm pretty sure I know who you are so say hello to your Dad for me.

After speaking with some friends on the rock, it was a real learning experience for them. Some were ready and had their BOB's ready, others were scrambling up to higher ground with nothing but their PJ's on. Everyone was "shaken Up" to say the least, and I'm so glad all is well. I'm wondering how many will get Earthquake Insurance now?

reply to post by Olivine


Yes, the lack of quakes in that region is concerning on a number of levels. First it may indicate why such huge quakes have occurred there before. The stress accumulates in the locked zone, and when it finally goes, it goes bigtime. All the geological evidence, as Mike has been pointing out, supports this- so it really puts into perspective more of the many factors involved.

Perhaps what we are seeing are the telltale signs, with the stress relieving first at the extremities of the fault. Again, that is concerning in itself because now across the entire fault, the mid portion you speak of will likely bear and be loaded with additional stress.

But hey, maybe all these quakes are good, and we have another century or two like Mike says.

As to today's quake, pretty sure we won't see much more of a drop in magnitude. That thing rang the earth like a bell for a couple hours, as 7.5's will. It had all the hallmarks and signature of at least a 7.3, on a bad day. The wavelength measurements alone of the S-waves supports 7.3 to 7.5 easily. In spectro mode I saw those plainly.

EDIT: and yup, even LDEO agrees this was a 7.5:
2013 1 5 8 58 32.0 55.75 -135.25 33.0 7.5 OFF COAST OF SOUTHEASTERN ALASKA
www.ldeo.columbia.edu...

Pretty much done deal once they post, and if it drops (unusual for them) it MIGHT drop up to .2 points max.

reply to post by Olivine

I'm also slowly developing his gray hair...

Back to the quake... I was wondering if a downgrade might occur, because a lot of the stations reporting in had that quake at somewhat less than 7.5. So, I guess we'll see. I mean, to take it down below say a 7.0 would be a massive downgrade in terms of energy release, so I'm dubious if they'd move it down as low as (say) 6.9, but okay, they might go down to 7.1 or 7.2.

However, the quake from October 28 2012 finally got upgraded from 7.7 to 7.8, which really surprised me. At least, the tectonic summary you linked to from USGS refers to it as a 7.8. And I'm pretty certain it wasn't upgraded during the week that it showed on the main maps. Earthquakes Canada still lists it as 7.7, though. (Readers, just scroll down in the Canada list till you find the mag 7.7 of Oct 28.)

For anyone who might think that a 0.1 difference in magnitude in the 7 range is no big deal, a mag 7.7 releases as much energy as about 350 mag 6.0 quakes, but a mag 7.8 releases about 500 times as much energy as a mag 6.0.

If you got hit by a fairly shallow mag 6 quake, you'd know about it! So imagine what a difference the energy equivalent of 150 magnitude 6.0 quakes can mean!

So when it gets up into the higher magnitude ranges, the small looking differences are not really so minor in terms of the energy involved. That's why we fuss over them.

the fault line on the west coast of america is sliping.
it will not take long until the rest slips.
then the west coast falls into the sea.

if I was you and you can do it.
I would move to the east coast.
it could happen any day now.

The Back Projections are available for today's earthquake.

The back projections model the earth rupture based on P-wave energy, using 3 different arrays from the Global Seismic Network.

You'll just need to click the "play" arrow directly under the main image. (It's just above the "Download 213.7kb" link).

This link shows the vertical GMV (Ground Motion Visualization) across the USArray. It's really interesting to watch the waves ripple across America--they use red for upward motion and blue for down--it's patriotic.

Originally posted by Patriotsrevenge
Years ago when we did the Experiment in earthquake prediction thread I caught on to something. Every time Alaska has one Japan has one just days after. Some how they effect each other. I would keep your eyes glued to Japan, since this was a big one they may have the mother of all recorded quakes there after the 9.0 and how that area is still shaking.

yeah that is true, the last big earthquake Anchorage had I think it was a 7.0, I can't remember the date but I posted about it in the 2012 earthquake thread. About 4 days later Japan got hit by one that was slightly bigger.

reply to post by TrueAmerican


Three days ago I saw weird clouds here on the West Coast of Ca unlike any I normally see it lasted most of the day.

Looking online I found people were calling the same type clouds "earthquake clouds" and that they according to one scientist can portend an earthquake from days to average of 30 days to a few months.

I am waiting to see.

Interesting description here can't be copy pasted

Notice they show China actually predicted a quake by these clouds.

www.terraresearch.net...

Clouds were toward the So end of the plate at the CA/Or border, there were very weird clouds again yesterday but not like the first "snake" cloud>

Originally posted by LightningStrikesHere

Originally posted by TrueAmerican

Originally posted by LightningStrikesHere
so is CA coast safe ?

That depends on who you talk to, when speaking for the near future.

Anyway, the minute this quake happened, I checked for potential triggering at our big volcanic beasts, YS and LV. No action, so it appears that all is well for now.

But I do know this much: if Cascadia goes and all hell breaks loose on the west coast, NO ONE will be able to say they didn't know it was coming. Cascadia has been warning us for years with big quakes up and down its length, and combined with all the other evidence, the time is ripe.

Yeah the west coast is safe...haha

edit on Sat Jan 5th 2013 by TrueAmerican because: (no reason given)

so where would you sugest a safe place be ? if this Cascadia happens

I found a map for our area online, a government produced inundation map which takes into account past tsunamis to show what will be under water in the future. They are listed by county.

According to our map we would be surrounded by water on all sides but it would leave a small area of homes dry including ours (hope they are right)! We are only 50 ft above sea lvl.

Originally posted by JustMike
reply to post by TrueAmerican

 

If it were to unzip along the entire length then it will be a very bad day.

That's one very long zone, so it could have intense shaking for up ten minutes and it could peak out in the low to mid 9 range.

As for the potential tsunamis, the worry there is that there could be several. While that's pretty typical, some could overlap and cumulate into larger ones.

I suspect this might have happened with some previous ones. Hard to imagine how else they could get a 30 metre high tsunami in places otherwise -- even allowing for topographical variations.

Mate, I hope you'll be a very old man (at least) before that happens. In which case I'd likely have to be the oldest man on Earth. But if it'll hold off for a few more decades and just twitch a little with 7s from time to time to keep people alert and practised with their drills, that would be help.

edit on 5/1/13 by JustMike because: (no reason given)

Our alert siren went off a few weeks ago and there was no notice of a drill, we checked the TV and no emergency broadcast and we went back to eating breakfast as the siren waled...only later did I remembered they said it would only be a 12 min or so warning if the underwater slide area offshore went! Probably would not reach the broadcasting stage..Don't think our community is ready at all!

Originally posted by The Undertaker
reply to post by Rockbeard

 

Nice to see a fellow Sitkan on here, I thought I was the only one. We still have a house on Baranoff I. and three years ago when we purchased a Earthquake rider on our insurance policy our agent laughed at us. He asked if we knew something they didn't because we were about the only ones he knew of that had Earthquake Insurance. Who's laughing now Carl? Anyway Rockbeard, I'm pretty sure I know who you are so say hello to your Dad for me.

After speaking with some friends on the rock, it was a real learning experience for them. Some were ready and had their BOB's ready, others were scrambling up to higher ground with nothing but their PJ's on. Everyone was "shaken Up"

to say the least, and I'm so glad all is well. I'm wondering how many will get Earthquake Insurance now?

They offered us earthquake insurance, added to our policy it would be 1,400.00 more a year, we can't afford it.

Originally posted by Char-Lee
reply to post by TrueAmerican

 

Three days ago I saw weird clouds here on the West Coast of Ca unlike any I normally see it lasted most of the day.

Looking online I found people were calling the same type clouds "earthquake clouds" and that they according to one scientist can portend an earthquake from days to average of 30 days to a few months.

I am waiting to see.

Interesting description here can't be copy pasted

Notice they show China actually predicted a quake by these clouds.

www.terraresearch.net...

Clouds were toward the So end of the plate at the CA/Or border, there were very weird clouds again yesterday but not like the first "snake" cloud>

edit on 5-1-2013 by Char-Lee because: (no reason given)

edit on 5-1-2013 by Char-Lee because: (no reason given)

Im in the SF bay area, right on the Hayward fault, and I saw the same clouds, it kinda freaked me out. Ive only seen them a few times in several years, and last week they started in the morning and lasted all day, all over the sky, right above the faultline. I thought "oh, pretty!" then I thought "earthquake clouds, oh, sh*t."
/

reply to post by TrueAmerican


I was on the northern tip of Vancouver Island when the 7.5 earthquake hit. I was sleeping like a baby. I did post a few days ago that I thought bigger ones were coming after the 3.9 just a while back...I was right!! It is always good to be prepared.

reply to post by JustMike


Thanks for all the updates, and I do hope everyone is safe. That area and the whole pacific 'ring of fire' area has seen a recent increase in activity. I am attaching a site that I use as reference on a daily basis. It is reporting two major quakes near Alaska over the last 11 hours. If you click on the orange spots it gives you a brief discription. In the Alaska area you can see the two overlayed on each other you just have to carefully scroll your cursor over to see the first and second one. Then if you scroll down the page you will see all of the current and active earthquakes worldwide.

Thought this would be helpful information.
Live Earthquakes Map

Edit: It looks like the map (real time) was just updated to show a 5.4 magnitude in that same area.

Best regards to everyone!!

Okay....so TA and JustMike...I need a little clarification. I'm a bit confused with these recent large quakes up there along the Canadian shore.

Both the Queen Charlotte and now this quake...what, exactly caused these? Because immediately after these quakes, it was believed, based on motion, that they were both thrust events. Now it is being said they are strike-slip.

So what is it, and what changed in the info to change that data? Is the CSZ the source or not? Are there fractures coming off the CSZ causing these? Both scenarios paint a possibly scary picture...but I just don't understand how scientist can say these are thrust events and then change it to strike-slip??

Also, based on the after-shocks for both quakes, it seems rather evident that even if the CSZ wasn't the mehanism for the main event, she certainly is feeling them. I would love the see a map that shows the main quakes and after-shocks for both of these at once...what kind of image that would paint. I think it would be rather evident that whole North end of the CSZ is humming.

ETA: Oh, and TA..anyone would be welcome to take shelter in my home should the 'big one' hit,but although we have a good bug-out bag and some plans, I am pretty sure my house would fall just like anyone else's. My biggest concern is if any of the three dams up river of me go (baker or ross being the worst). We are in the flats and the route to get up would most likely be disrupted....so it would be up on the roof and that, my friend, is most likely not going to be high enough. We're talking a wall of water nearly 100 ft high rushing down into our valley....pray THAT never happens.


ETA again: Ouch! Nice little after shock just hit. I am going to peg it at close to 5 and probably south, because I have a southern station up and it's coming through nice and sharp!!

I'm interested in seeing if Phage was right when he wrote down January 27th. Will a big earthquake strike on or very near that date?

Originally posted by RussianScientists
I'm interested in seeing if Phage was right when he wrote down January 27th. Will a big earthquake strike on or very near that date?

Does someone have a link to what Phage posted? If Phage is giving info about a possible date, I'm getting the heck out of here.

earthquake.usgs.gov...


since the 7.5 mag quake hit , so far we v got 14 quakes in total t the smallest of which is a mag 3.5

to me it looks like there should be more aftershocks ... tho i could be wrong ...

MAG UTC DATE-TIME y/m/d h:m:s LAT deg LON deg DEPTH km Region MAP 4.2 2013/01/05 20:43:17 55.473 -135.318 7.7 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 3.9 2013/01/05 19:53:22 55.570 -135.074 5.6 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 4.4 2013/01/05 15:41:43 55.622 -135.154 9.9 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 4.0 2013/01/05 15:32:15 55.485 -134.904 10.0 SOUTHEASTERN ALASKA MAP 3.5 2013/01/05 13:45:14 55.412 -135.034 10.0 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 5.1 2013/01/05 12:28:30 55.235 -134.527 9.8 SOUTHEASTERN ALASKA MAP 3.7 2013/01/05 12:24:44 55.593 -135.124 14.9 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 3.8 2013/01/05 12:05:52 55.896 -135.455 10.0 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 4.0 2013/01/05 11:39:37 55.520 -135.087 9.9 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 4.8 2013/01/05 10:11:16 55.759 -135.451 7.0 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 4.2 2013/01/05 09:41:25 55.736 -135.211 16.2 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 4.5 2013/01/05 09:32:08 55.102 -134.634 9.2 SOUTHEASTERN ALASKA MAP 4.7 2013/01/05 09:27:20 55.541 -135.252 9.9 OFF THE COAST OF SOUTHEASTERN ALASKA MAP 7.5 2013/01/05 08:58:19 55.368 -134.621 9.8 SOUTHEASTERN ALASKA

At the very least this quake should serve as a reminder that everyone living near the coast along the ring of fire should be prepared(which does seem to be the case).

So much for the Illuminatti's headquarters lol....