Could the 6.4 quake (9/9/11) in Vancouver be a foreshock to a mega quake?

there are currently 7 unidentified quakes on the 9th (Day 252), but they are less than Mag 2
heres the clearest IRIS graph I could find for PB.B012, Ucluelet, BC, CA Plate Boundary Observatory Borehole Seismic Network, EH1 channel
www.iris.edu...

and heres the quakes as identified by EQ Canada marked on that

thumbnail


full size image

Notes:
* there seems to be a 25 second arrival time delay on all the quakes to PB.B012
* double coloured tags represent a quake that carried on and moved down a line and then changed colour

I'm going to have a look at the other days since too, a bit harder to break down as the graphs go all messy with interference, and the scale is different, I couldn't get the scale thingy to work on BUDQuack this morning

@ curiouswa, I say with 99% certainty that the 4.9 they were talking about is the 4.5 on the lists and graphs, because siesmos don't lie

just wanted to leave a quick update from the Canadian Earthquake site -

13:00 PDT September 11 - Aftershock Update: Friday's M 6.3 earthquake off the west coast of Vancouver Island was followed by more than 100 aftershocks. The largest aftershock occurred 3 minutes after the earthquake and had magnitude 4.9. The remaining aftershocks were in the magnitude 1-3 range and approximately 50 km offshore, thus too small and too far offshore to be felt or cause any damage. The rate of aftershocks has been decreasing steadily, down to near zero during the past few hours.

earthquakescanada.nrcan.gc.ca...

not directed at you personally wrdwzrd ( as the messenger) but where the heck are they then?
I see 35 on their list and have ID'd 16 possible unidentified quakes in the first 36 hrs after the main shock.
I just looked this morning and they had 3 more new items on the list for the 10th inc. the biggest one on the IRIS graph a mag 3
This is going to be a long drawnout task if we are looking for Mag 1's

heres my take on the 10th (Day 253) same station and channel clean graph off IRIS

thumbnail


full size graph

Excellent Muzzy! Thank you for the graph and link.

I have a lot of questions too...and have not heard back yet from the USGS.

My only thought in the lack of documented info, is that perhaps they are still studying it??? I dunno...

reply to post by westcoast


Are you talking about the one I showed you or something else. I MUST find out what's causing all this stuff in the south

Originally posted by westcoast
Here is a copy of the message I just sent USGS (via their message page). They have always answered me in the past with a personal response. I will let you know what they say.

I am wondering why none of the larger after-shocks have been recorded by USGS for the 6.4 Vancouver quake on Sept. 9th?

According to local reports, and by simply looking at some of the near-by seismograph stations, it is very clear that there were several above the 3.5 threshold.

Earthquake Canada finally started listing some of them on Monday, but also in contradiction to local reports, they only have one above the the 3.5 USGS reporting threshold:
2011/09/09 19:44:43 49.36N 127.21W 35.1 4.5ML 88 km WSW of Gold R.,BC

Yet....this is STILL not listed on your site.

In light of the fact that a lack of after-shocks can sometimes be an indicator of a possible larger event (making the 6.4 a fore-shock), I would think the USGS would want to keep the public informed with accurate information. Especially since we just had a three month early ETS event in the same area.

Could you tell me why these aren't being reported?

Thank you for your time,

Txxxxxxx

Also of note....small quake showng on my nearest station to vancouver....but it is a bit distant.

Here's the response:

Hello,

Actually, our threshold for showing quakes outside the United States is magnitude 4.5 or greater - but that is not an absolute number. Those magnitude readings
are also as we calculate them. An example of the differences in calculated magnitudes would be a quake on 9/12 at 9:37 UTC off Vancouver Island. The Canadian
earthquake network has it as a magnitude 4.6 while we calculated it as a magnitude 4.2. We do show this quake on our site though, showing that we do not always
stick to the mag 4.5 threshold. Even by Canadian calculated magnitudes, there have only been two at 4.5 or higher since the original 6.4 quake. Both of those were
calculated by the USGS lower than the 4.5 + threshold (although we did show the mag 4.2).


Good day,

Ken Dixon
USGS Office of Communications & Publications
Science Information Services - Alaska

Hmmm.....not much of an answer, IMHO.

Take a look at just todays quake list:

MAP 4.5 2011/09/13 23:18:27 -24.368 179.901 505.6 SOUTH OF THE FIJI ISLANDS
MAP 3.0 2011/09/13 22:59:24 33.591 -86.672 5.0 BIRMINGHAM URBAN AREA, ALABAMA
MAP 4.8 2011/09/13 22:09:41 26.966 127.348 90.5 RYUKYU ISLANDS, JAPAN
MAP 3.0 2011/09/13 22:03:44 63.379 -148.951 101.6 CENTRAL ALASKA
MAP 4.7 2011/09/13 21:18:18 -37.204 -73.521 17.4 BIO-BIO, CHILE
MAP 2.8 2011/09/13 21:13:11 51.669 -171.877 36.7 FOX ISLANDS, ALEUTIAN ISLANDS, ALASKA
MAP 4.0 2011/09/13 20:18:10 32.105 -115.175 26.7 BAJA CALIFORNIA, MEXICO
MAP 4.4 2011/09/13 19:59:22 51.222 -175.989 47.5 ANDREANOF ISLANDS, ALEUTIAN IS., ALASKA
MAP 5.0 2011/09/13 16:19:30 34.409 23.704 24.2 CRETE, GREECE
MAP 2.9 2011/09/13 16:18:16 57.325 -156.825 19.3 ALASKA PENINSULA
MAP 2.6 2011/09/13 16:16:34 57.286 -156.790 17.4 ALASKA PENINSULA
MAP 4.1 2011/09/13 14:24:29 -4.671 143.938 97.4 NEW GUINEA, PAPUA NEW GUINEA
MAP 4.7 2011/09/13 14:14:34 38.720 142.343 59.6 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 2.6 2011/09/13 13:13:38 36.902 -104.848 5.0 NEW MEXICO
MAP 3.6 2011/09/13 12:27:14 35.730 -121.109 8.0 CENTRAL CALIFORNIA
MAP 2.5 2011/09/13 09:32:35 61.853 -150.402 13.7 SOUTHERN ALASKA
MAP 5.0 2011/09/13 09:10:20 35.201 141.263 27.5 NEAR THE EAST COAST OF HONSHU, JAPAN
MAP 4.8 2011/09/13 08:27:36 -6.907 143.868 10.0 NEW GUINEA, PAPUA NEW GUINEA
MAP 5.2 2011/09/13 07:56:10 -6.879 143.932 15.5 NEW GUINEA, PAPUA NEW GUINEA
MAP 2.5 2011/09/13 07:21:36 32.797 -100.842 5.1 WESTERN TEXAS
MAP 3.1 2011/09/13 07:00:53 51.796 -171.508 26.0 FOX ISLANDS, ALEUTIAN ISLANDS, ALASKA
MAP 2.5 2011/09/13 05:47:35 36.428 -117.844 7.3 CENTRAL CALIFORNIA
MAP 2.5 2011/09/13 05:46:40 37.042 -104.813 4.9 COLORADO
MAP 4.0 2011/09/13 05:24:40 36.943 -104.756 5.0 NEW MEXICO
MAP 5.7 2011/09/13 04:49:38 5.633 -77.502 25.7 NEAR THE WEST COAST OF COLOMBIA
MAP 5.0 2011/09/13 04:38:49 5.635 -77.534 18.9 NEAR THE WEST COAST OF COLOMBIA
MAP 3.4 2011/09/13 04:34:05 58.344 -153.920 68.1 KODIAK ISLAND REGION, ALASKA
MAP 2.6 2011/09/13 02:59:14 36.975 -104.766 9.0 NEW MEXICO
MAP 3.4 2011/09/13 01:37:19 36.976 -104.849 6.8 NEW MEXICO
MAP 4.2 2011/09/13 00:48:24 11.383 -86.708 60.6 NEAR THE COAST OF NICARAGUA

I see several that fall below the 4.5; how do they determine what to post?

reply to post by westcoast

I see several that fall below the 4.5; how do they determine what to post?

Doesn't seem they follow their own regulations

Thanks for reposting the list - I was reminded of the
Alabama quake again, not a usual location..

Source

Worldwide earthquakes with M4.5+ located by USGS and Contributing Agencies.
(Earthquakes with M2.5+ within the United States and adjacent areas.)

Are all the ones you saw listed that were under 4.5 in the US or surrounding area?

reply to post by onthelookout


For example; the 4.0 in Mexico and the 4.1 in New guinea.

We have a 6.4 quake sitting right off our coast, that could very well either be part of the subduction zone or trigger it....and the USGS is just ignoring it??!!!

Doesn't make sense.

reply to post by westcoast

Oh I agree...sorry I didn't go through your list because the pizza guy was at the door and I was hungry!

I'm uneasy about ALL of it.

reply to post by onthelookout


mmmmm.....pizza sounds good!

I sent another response to USGS asking why they chose to list some and not others. Also, if the have ever considered including the Vancouver area into the 2.5 threshold since it involves the Northern end of the Cascadian Subduction Zone...would make sense to me!

Originally posted by muzzy
there are currently 7 unidentified quakes on the 9th (Day 252), but they are less than Mag 2
heres the clearest IRIS graph I could find for PB.B012, Ucluelet, BC, CA Plate Boundary Observatory Borehole Seismic Network, EH1 channel
www.iris.edu...

and heres the quakes as identified by EQ Canada marked on that

thumbnail


full size image

Notes:
* there seems to be a 25 second arrival time delay on all the quakes to PB.B012
* double coloured tags represent a quake that carried on and moved down a line and then changed colour

I'm going to have a look at the other days since too, a bit harder to break down as the graphs go all messy with interference, and the scale is different, I couldn't get the scale thingy to work on BUDQuack this morning

@ curiouswa, I say with 99% certainty that the 4.9 they were talking about is the 4.5 on the lists and graphs, because siesmos don't lie

edit on 13-9-2011 by muzzy because: forgot the slash in the image

Muzzy....I am quoting this post so I can reference the first aftershock. I've gone through each day since that main quake and every single notable aftershock has that same wierd 'shape' or signature. I was seeing this on GEE too...but figured it was because of distance, but now I am not so sure. Do you see what I mean? Seems more like loud rumbles vs. a sharp quake. Am I seeing things here???

reply to post by westcoast

can you post a couple of links to what you mean?, I've seen the live PB102 GEE graph today but there was nothing on it. I notice its on the BHZ channel, that might have something to do with the shape of the traces, I seen one somewhere else and the bigger quakes were cropped, like Geonet does here.
I've read your Topic on reading the GEE and I had it up and running but to me its hard to read, maybe its the way I've got it set up.

I suppose one good thing is the aftershocks are at right angles to the Plate edge, rather than running parallel with it which would maybe weaken other points along the edge.
I ran the EQ Canada reported aftershock series through GPSVis with numbers for each day 1-5, they seem to have gone out 24.8km from the epi center at first and now returned back towards the edge.
Kind of depends on where the other 65 aftershocks (of the 100+) were at
numbered aftershock map


thats an interesting submarine feature at Ououkinsh Canyon 50.016779°, -128.178503°, 100km NW of the event, wonder what thats about

reply to post by muzzy


HERE is a good example. Only one on the graph...nice big black blob in the center.

Sup. How's that foreshock working out for you?

Exactly.

More ridiculous scaremongering.

reply to post by Logman


Based on your avatar and signature it will take a much more intelligent comment than this to make any kind of conversation with you worth my time.

That foreshock is working just fine, BTW....would love it if nothing comes of it. Just for education purposes for anyone who wants to actually learn something, it could still be awhile before a larger event occured. Obviously, the more time that passes the safer it is, but it's only been a few days. Certainly not out of the woods yet.

Originally posted by Logman
Sup. How's that foreshock working out for you?

Exactly.

More ridiculous scaremongering.

Hey, WC is just trying to make people AWARE.... if nothing comes of this, GREAT..... but knowledge is power, and being prepared for something is nothing to scoff at.

How bout you take your absolute negativity somewhere else and let people discuss possibilities?

That foreshock is working just fine, BTW....would love it if nothing comes of it. Just for education purposes for anyone who wants to actually learn something, it could still be awhile before a larger event occured. Obviously, the more time that passes the safer it is, but it's only been a few days. Certainly not out of the woods yet.

As long as we live on Earth, we are not out of the woods. I for one am glad that some of us have the intelligence to want to know the possibilities.

I may sound a little crazy, but I have been having anxiety lately, and that usually points to something happening. I am by no means predicting anything at all, just being aware of my surroundings.

Love and peace to all.