45+ Aftershocks From Yesterday's 7.7 EQ in Canada, Multiple 5 and 6-pointers Continue to Hit The Area, Eerily Reminiscent of Honshu EQ

We had a 6.6 last year, same slip and strike. Not nearly as many aftershocks as this one though. IMO, this is a swarm.

4.9 now

Last Edited by Too Dark Park on 10/28/2012 07:56 PM

another 4,7

Blazar is very,very close now. Blazar 12/21/12

Does anyone know when the last ETS was recorded on the Cascadia subduction zone? I understand this occurs every 12+ months or so.

[link to www.earthquakescanada.nrcan.gc.ca]

[link to www.earthquakescanada.nrcan.gc.ca]

Okay, here it is:

[link to pbo.unavco.org]

Last ETS episode on Cascadia seems to have begun in August 2011. So the next one is due any time. This is not good, in light of yesterday's action in Haida Gwaii.

there is a huge difference between a 7.7 and 6.6 though.

I think they occur closer to every 18 months, however, each time I have tried to find a date in the past, the information could never be found. Let us know if you find something though.

@curiouslyinterested: Just posted. The last one started in August 2011, earlier than anticipated. It had been expected in October 2011. So here we are, 15 months since the previous ETS episode began.

For anyone who's interested: [link to pbo.unavco.org]

On page 6 of this thread, I laid out the ETS timeline and link for slow slip as well as my personal thoughts on this. Is there something I or we can help you think about?, like where you are heading with your thoughts?....

Love some questions and alternate opinions on anything seen so far.

Magnitude 4.1 - HECATE STRAIT REGION, CANADA

[link to earthquake.usgs.gov]

how is Haida Gwaii a land mass?
land elevation? being pushed up?

4.1 now


[link to earthquake.usgs.gov]

@Redpaw: I see 2012 event is over:

[link to www.pnsn.org]

The Queen Charlotte Islands earthquake of 1949 was a magnitude 8.1 interplate earthquake that struck the sparsely populated Queen Charlotte Islands and the Pacific Northwest coast on August 22, 1949. The main shock epicenter began in the ocean bottom just offshore of the rugged coast of Graham Island. It ruptured along the Queen Charlotte Fault both northward and southward more than 500 km (311 mi). Shaking was felt throughout British Columbia, parts of Washington, Oregon, Alberta, the Yukon, and Alaska. No deaths were reported in this earthquake.

Going a little nuts there...


[link to www.earthquakescanada.nrcan.gc.ca]

Isn´t there any damage in that area ?
Not in the news ?

There has been very little damage, that area is very sparsely inhabited.

@Redpaw: Locked, but will it be unlocked, causing a reversal as outlined in the links I posted? It's so close to the ETS last movement; high tide combined with the quake yesterday cannot be a good thing.

This ETS movement wasn't known when the last Queen Charlotte Islands earthquake occurred.

First time posting on GLP.
Just wanted to add to a few others comments, we're very fortunate thus far, in that the areas getting rocked off our west coast are very sparsely populated.

No real infrastructure to damage.
Thanks for continuing to follow and update this, guys. :)

this is more like a harmonic tremor

Welcome!

Do you remember this area being hit like this before?

Seems very rare.

My Earthquake tracker keeps going off every half hour with another hit.

Anything over 4.0 within 500 miles and I am in Seattle, So i am getting updates a lot.

Thanks both of you.

1949, look a few posts up or wiki

I hope I am wrong but we are now in the Foreshock Sequence before a major event on the Cascadia Subduction Zone.

I was incorrect in the information I had posted earlier regarding the Tohuku quake.

From the USGS site it says:

"The March 11
earthquake was preceded by a series of large
foreshocks over the previous two days, beginning on
March 9th with a M7.2 event approximately 40 km
from the epicenter of the March 11 earthquake, and
continuing with another three earthquakes greater
than M6 on the same day."

This link takes awhile to download but it extremely detailed slides including the foreshock data
[link to earthquake.usgs.gov]

The Queen Charlotte Fault is on the boundary of the Cascadia Subuction Zone. There is a great color graphic explaining the plates in the area here
[link to commons.bcit.ca]

This pattern is identical and if we can extrapolate a similar timeline, we may see a >M9.0 in a little over 24 hours.

hehe I haven't yet figured out how to properly quote people, so.. @littlemiracles thanks very much! :)

@I am Shelk I haven't, I know it happened decades ago though.

The region is still getting moderately big aftershocks in the 4-5 range. couple every hour.

those quakes making me concernend since the 7.7 yesterday. as i use a EQ alert browser plugin, i never saw that region shake that much before.

i really hope you´re wrong
but something tells me, we´re up for a big one on the west coast while east coast gets slammed by Sandy.

Last Edited by Doomina on 10/28/2012 09:16 PM

Another way to put this in perspective:

Look at the graphic of the plates.

The Queen Charlotte Fault & San Andreas Fault are BOTH identical TRANSFORM faults. They both connect to the Cascadia Subduction Zone

If it was the north end of the San Andreas that went off M7.7 yesterday people would be FREAKING OUT about this being the possible trigger to the 'BIG ONE' on the CSZ.

The Queen Charlotte Fault is the same warning, it just happens to be the NORTH trigger versus the SOUTH one.