Whats going on with the Antarctic Plate?

I have been watching the area south of me (New Zealand) for a few years now for earthquakes, anything south of -46.0 I call the Southern Ocean or Antarctic Region.
I have the Global Live Internet Seismic Server (LISS) station SNZO Seismogram page set as my homepage on Firefox, so everytime I open up I can see whats going on around our area.

So yesterday when I opened up there was a bit of action going on, looked like quite a big quake that lasted a long time, at least an hour


What was interseting was the two pulses within the main wave.
So the next step (when there is something worth looking further into) is to check the USGS list and see where they were at.
So I go to
USGS 7days
earthquake.usgs.gov...
The page will keep rolling over as time goes on so I took a screenshot of the day n question


As you can see there were in fact two quakes within a minute of each other but quite a ways apart
6.4 Burma-India Border
5.7 Vanuatu

The reason the two waves seem the same siz is because of the distance from SNZO, Vanuatu being closer.

The next step is to see what other stations on the LISS are showing at that time. For those not familar with the LISS network the stations are shown on this map page
aslwww.cr.usgs.gov...

I again took screenshots of some of the stations in the Austalasian area, and have marked identifiable quakes from the USGS list with the distance of each quake from the station, and how long it took the P wave to reach the station (taken from Phase Arrival data available under Sceintific and Technical tab on each individual USGS quake page). In some cases I had to use other Networks to get this info
EMSC European-Mediterranean Seismological Centre
www.emsc-csem.org...
GFZ German Research Centre for Geosciences
geofon.gfz-potsdam.de...
As you can see the stations start to show quite clearly that there were two individual quakes.






once the stations get closer to Vanuatu the two meld together


and back to SNZO now with the quakes ID'd


Now, you may be wondering what the signals that have a red circle around them are?

Well I don't know
they don't match up with anything on any lists time wise, including Geonet and Geoscience Australia.

I think there is a lot more going on in the Southern Ocean and Antarctica/Antarctic Plate than the people who are supposed to be monitoring these thngs are letting on.


some other sources I used to compile the graph tags
Time Difference Calculator
www.grun1.com...
Calculate distance between Latitude/Longitude points
www.movable-type.co.uk...

I have noticed these unidentifed signals for a couple of years since I found LISS, they happen on a quite regular basis, sometimes they might show up weeks later on the usgs lists (8-30days) but more often than not they are never ID'd.
And these are not small quakes either, when you compare the size of the waves.

As it happens there was another one the day before, still unidentified at this time.

reply to post by muzzy


Shoot this data over to member Puterman, he is the resident expert on seismographs. This definitely looks odd but it could just be an aftershock, but then again, I know next to nothing about this sort of stuff. Well thought out post, S+F

Theres a whole lot of shaking going on thats for sure,i noticed the USGS mainly covers everywhere else but europe as on the third at 330am I started a study of global earth movements for 24 hours and recorded 27,but by visiting this sight only had 22 with no european stuff,central eastern europe has had a lot of quakes of late,i used physical observation on this link hisz.rsoe.hu...
and the study was on zorgons thread www.abovetopsecret.com...
So according to the USGS thats 34 from 330 on the 4th -5th at 330 am ,not including europe,thats a lot.

www.emsc-csem.org... for Europe and other.

reply to post by muzzy

Thank you for the heads up on this thread and for the detailed info you have posted. As much as I try to remain an objective, critical thinker - willing to consider a range of explanations, I do have to admit that my level of concern does rise when the pattern and significance of omissions multiplies. (and this does make the Yellowstone deletions seem somewhat insignificant by comparison)
Thanks again - I look forward to following your future posts!

reply to post by Shenon


Thankyou,its quite scary the activity at the mo.

reply to post by muzzy


Bottom Image:

If you look at the Quack Query plot for this you cannot see that 10:01 bump at all.


I have often wondered how they produce these as I have NEVER seen one that looks like the plots you get elsewhere.

It does not show on the plot either which is a direct read of the SEED file, but you would need to download and read that file to see if there is a minor disturbance at that time.

The 20:02 (?) on does show on the VMZ channel very slightly but let's face it if you saw that on a Yellowstone recorder you would not even notice it. It does however show up well on the BHZ channel



On location 10 for the BHZ channel it shows better yet again slightly:



It looks as if it is distant, but actually the definition of the plot is fooling you. I downloaded the raw data for 6 of the channels on SNZO and picked 00.BHZ and 10.BHZ as the best two. This is 19:50 to 20:30 graphed. You can see straight away that it is a local quake.

[atsimg]http://files.abovetopsecret.com/images/member/e2e1b76f7042.gif[/atsimg]

I created a wave file and loaded it into Audacity. Here you can se it is a very clear sharp start.

[atsimg]http://files.abovetopsecret.com/images/member/194653f4b83d.png[/atsimg]

This is the spectrum

[atsimg]http://files.abovetopsecret.com/images/member/ddab47b6d347.png[/atsimg]

You can hear the tiddler in the sound byte for that quake.

IU_SNZO_BHZ_20110204-194958_1000Hz

My feeling is that this is local and so are the other small ones. I am guessing under 1.0 and probably too small to be registered on most systems. As to why they show so clearly on the LISS plots I don't know. As I said this is something I have often wondered.

My 2c anyway.

reply to post by PuterMan

I was typing away replying to this 2 days ago and our Broadband crashed in the middle of it.
Have had to buy a new modem and get Telecom to check the lines. Turns out our old modem was "out of date". Too bad there was no notice warning of this. Been having trouble for the whole of last week, kept losing the connection. Dealing with the NZTelecom Helpline based in the Phillipines has been very very frustrating.
Still not sorted, only have one computer up and running, and its not the one with all my link addresses. Have to exchange the new modem for a wireless one so I can use my laptop.

Anyway.,
Thanks for looking into this

You may be right about them being local on SNZO.
I wonder if those two red circled signals are these?

3460102, -38.90316, 177.97539, 2011/2/4 10:5:48, 24, 3.054, o/s, E of Wharerata, Gisborne, O/S Warerata, Gisborne Swarm

3460266, -42.48123, 173.76868, 2011/2/4 20:2:28, 5, 3.996, SE of Kaikoura, Canterbury, Felt

The first one seems awfully small to show such a big signal on LISS. And there have been bigger quakes in that Swarm that I didn't notice on LISS.

If that explains SNZO, what about the other stations?
I've seen nothing on Geoscience Australia that would match up time wise.

reply to post by muzzy

Hello Muzzy - I have been paying greater attention to activity in your neck of the woods and trying to get some perspective on what baseline 'normal' activity might be. Since Vanuatu seemed to figure prominently I began to review activity in the past year and I was completely awed by the frequency and significance of earthquake & volcano activity 2010-2011 so far. (remember I had only been watching the rather passive North American region) While I recognize Vanuatu is situated at an active region I have to inquire whether what is happening currently in this region is anywhere close to 'normal' based on your observations.