This is the best article so far on the Banda Aceh quakes. So I decided to Reblog it.
Earlier I posted an info bulletin about this morning’s Banda Aceh earthquake. Rather than muddle it with more and more stuff, I thought it might be better to include this update as a separate post, as it is more of a discussion than a news piece in any case.
The truth is that this earthquake is properly strange.
The part of the Indian Ocean in which this earthquake occurred has two very different types of geologic structure very close to each other; there is the Ninetyeast ridge – a volcanically produced range, and a destructive margin subducting the Indian plate eastwards under the Pacific margin. It is important to note (in the context of this earthquake at least) that the sea floor under the Ninetyeast ridge was originally produced by standard constructive margin seafloor spreading.
These two structures are shown quite nicely in this image taken from GeoMapApp, with…
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I know, Reblogs is often a sign of a lazy mind. But this one was to good to skip really.
I promise that it will not happen often.
The Mexican quakes are showing up on Hekla SILS.
Hekla is really starting to turn out to be a world class teleseism network on it’s own.
The borehole strainmeters is slowly moving down on the scale needed for the quakes to be shown.
It is though not as beautifully clear as the Sumatran quakes.
Great find, Carl (or I think it was Renato in the last thread, thanks both).
Meanwhile, strainmeters in Hekla are showing another (external?) earthquake this morning:
And another thing, today is my moving day, so after I leave this place later in the afternoon, I’ll be without proper internet access for a while (not sure how quickly I can get internet in my new place). So have fun and see you in a few days (I hope).
Ah just saw that I duplicated the comment above. 🙂
Blame it on general moving scatterbrainedness and lack of coffee (better go and make another cup right now)!
It was the Gulf of California 6.9M quake that you see.
There was a 6.2 earlier at roughly the same location, that is visible as a small blipp in between the larger ones.
Good luck with the move; hope it goes well. See you soon 🙂
It was Renato who had fished it out from Eriks, where Sherine had posted it.
To give it a precise legend 🙂
Good luck with the moving, your new job and everything!
See you soon!
these EQ happenend around the Equator, with the axis changing and the bulge of the EQ changing, could the plates seperate? there are now 40 EQ between 10-30km dept, listed in two distinct lines, like a zip
The plates that are separating are always separating at quakes belonging to separation.
The earths plates are always moving about. Nothing new or exceptional in that.
I used the wrong way in saying it, better have an early night and look at it tomorrow
A few pictures for those, like me, who missed Etna last night:
Isn’t Etna a bit to frisky now?
It is not much more than a week between the paroxysms now… If this continues she will soon (a year or so) have pretty much continous eruptions.
But I might be terribly wrong here.
I don’t knw Etna well at all so I can’t really say.
Wikipedia says that Etna is almost constantly erupting: http://en.wikipedia.org/wiki/Mount_Etna
I meant more like the paroxysms themselves coming closer and closer together.
Technically Wiki is correct, Etnas eruption is counted as continous, but I meant the general sprout-moments that we through Boris has come to know and love as Paroxysmal events.
Apparently the Sumatra EQ woke Bob up. Earthquake Report is saying that the stain has been seen again:
Or this might have something to do with it:
2012/04/11 19:39:10.18 27.7365 -17.9937 26.10 km 1.30 mbLg 1137979 S FRONTERA.IHI
Thank you for the re-blog above.
Read somewhere that geologists are puzzled about the fact that the strike-slip EQs were so large (i.e. greater than 8.0)? Is that because previously observed ones have been smaller? Or is it because of assumptions in the modelling for strike-slip faults?
Both are actually supposed to be 8M maximum. The thickness of the crust is not supposed to be able to bear more. And no strike-slip has been previously recorded at these levels.
I actually have an idea about the why, but I am saving that for a post that I will be writing later today. If I get the time…
Icelandic geologist Páll Einarsson re. the Banda Aceh quake in MBL: http://www.mbl.is/frettir/innlent/2012/04/11/pall_skjalftinn_um_margt_serstakur/
(You’ll have to use a translation machine, cause it is in Icelandic.)
So thats the Mexico quake I’m reading at Hekla ?
Yes, the small recent ‘blip’ at about o8:00 or thereabouts.
O Tremore (sung in my best impersonation of a famous Italian tenor – no skip that, that’s a visual none of us need)..
Totally OT, but is Finland Scandinavian or merely Nordic?
Geologically, culturally, or in general political area?
1. Geologically it is not a part of the Scandian mountain, nor the scandian Sub-plate. We are actually being pushed to them, and slghtly upwards, each year.
2. Culturally they belong to the Scandinavians, they just have a really different language. They are also Nordic, and part of the Baltics. Biggest difference being depressed, imbrabeable, and pretty much unbeatable. Oh, and the knifes 😉 Actually Fins are awesome, but never tell ’em.
3. Politically they are Scandinavians. Actually they where one country up untill 1809 when we lost them our brothers due to a stupendously stupid King.
Culturally, the Finns are Finno-Ugrians and quite different from us Indo-Europeans. Their origin stretches back eastwards along the permafrost boundary to a point of origin east of Lake Baikal. Germanic, Slavonic and Latin peoples have far more in common with Indians than with Finns or Hungarians.
The Finns of today have the same culture as we other Europeans. And a lot of the Slavonic and a lot of the Germans also have traces of Mongolean or other Asian blood. If you think about all the Mongolean and Tartaran raids into Middle Europe in the Middle Ages and so …
A lot of German people today eg. have and had broad cheekbones and small eyes (and I don’t talk about people from recent immigrant origine here). I don’t understand why this should be an issue… 😕
Issue? Sorry Inge, you’ve lost me. I haven’t got a clue to what you mean by issue here? :confused:
“…Germanic, Slavonic and Latin peoples have far more in common with Indians than with Finns or Hungarians…”
What kind of Indians? Indian Indians or American Indians?
I am from the only family that I know of, that has had a full on feud with itself. It seems that one half of the family had a European Great Grandmother, the other half had a Choctaw Great Grandmother.
They didn’t get along so well.
Thanks Carl! I always thought they were Scandinavian but someone just pulled me up on it.
What a moron…
Technically they are fenno-scandians. Tell the one who told you to go and argue with a Fin… 🙂
ha, will do.
… with or without knives?
Doesn’t really matter… 😉
While the “Strombolian explosion” reported during the night were not a paroxysm, one has started an hour or so ago as confirmed by both tremor and thermal imagery from the revitalised INGV site.
Sorry, lost a word or two – “seems to”. I should have said “one seems to have started an hour or so ago as confirmed by both tremor and thermal imagery from the revitalised INGV site.”
If you take a look at the tremor plot, you’ll see the peak from yesterday’s Indonesian eqs almost bang on 24 hours ahead of today’s apparent paroxysm. Coincidental? While I believe so it will be fun to hear expert opinion and speculation on the subject.
The re-blog was very conformational, (Thanks for reposting it Dragon) on the idea that was bouncing around yesterday re: the peculiarity and the forces/vectors involved around the Ninetyeast ridge,
”Scientists do not agree on a direct relation in between earthquakes (even very powerful earthquakes) and volcano activity.” (Earthquake report/Armand Vervaeck)
Yep, I understand, difficult to put money where mouth is on this one. No-one want’s to be a doom-monger, or in the position of being shot as the messenger. Interesting that El Hierro 26.10km 1.30mblg you mention KarenZ, reminds me of a deep cough, or rather a huhgmph if you get my idea.
What is going on in the Gulf of California? 28.N -113.W
2012-04-12 10:26:55.0 10 5.0 , 2012-04-12 08:54:48.0 30 4.5
2012-04-12 07:57:32.8 10 4.2, 2012-04-12 07:15:48.0 10 6.9
2012-04-12 07:06:01.0 10 6.0, 2012-04-12 06:48:38.0 10 4.6
2012-04-09 21:37:09.0 15 4.2 ( http://www.emsc-csem.org/Earthquake/Map/zoom.php?key=84&typ=NAM#2 ) The 30 km at 08:54:48 stands out oddly.
Sounds as if the planet was struck like a bell, for want of a better phrase, whilst Alaska had a round of applause from the sidelines. ! Keep safe all.
Interesting foot note: The ”2012/04/08 14:03:43.5 51.401 1.663 5 1.9 19KM EAST OF MARGATE (courtesy of BGS.ac.uk)” that was posted April 10, 2012 at 16:38 on ”Why the VEI… ?” has now been removed from BGS. Political correctness or just a ghost?
Is the Ninety East Ridge really a former spreading center? I always thought it was the ‘tail’ of the Kerguelen hotspot. An extinct hotspot trail does not have any ‘inactive’ faults, which makes this theory pretty implausible.
Interesting point Pieter.
Thought the build-up of material may pose a problem to the subduction process.
It probably will in the future, but the ridge is still some 270km from the subduction zone.
There is also Australian/Indian plates convergent boundary (SW/NE, not sure of the bearing) that could be factored in to the equation. Could anyone with a name or reference for this?
* help with a name or ref’
Thursday April 12 2012, 13:02:28 UTC 15 minutes ago Sicily, Italy 2.1 8.0 CSEM-EMSC Feed Detail
Thursday April 12 2012, 12:57:10 UTC 21 minutes ago Sicily, Italy 2.9 5.0 CSEM-EMSC Feed
There definitely seems to be a paroxysm at Etna now – judging by the webcams!
Yes, just look at the rising “tremore volcanico” at INGV site!
Does anyone have a link to a decent, accurate map of plate tectonics? It seems all the ones I’m finding are inconsistent with each other.
Thanks for the feedback on Java’s quakes!
Now, for Plate Tectonics I use both the Wikipedia map and Google Earth’s:
And the Google enabled with the plate feature>
Hail Renato, and thank you! That’s exactly what I’m looking for. I’ve been using Google earth as well, and it seems these are the only two sources that show the Burma microplate and the fault that runs westward from it.
16min ago 37.89 N 15.62 E 8 ML 3.1 SICILY, ITALY
Hork. Missed most of Etna again.
No, you didn’t! It has just started and no fountain yet showing…
Judging by the IR view (Nicolosi) and comparing with the 200 or so m high “old” Southeast Crater, the fountains range between 400 and 600 m in height.
At least that’s what we’d see if it was night. 🙂
It’s still going I think – or it might just be the afterglow of the main event.
You did not miss it as it still working up to the main event. Tremot is still rising.
A triple snap answer! 😀
Looks like you’re probably right Woohoo 😀
What’s the best webcam – I’m using the INGV link but it takes ages to refresh. Is there a better one?
It appears that the colouds are closing in on Etnas summit.
Try this link.
Thanks, Doug! That’s much quicker! I’ve never ‘seen’ it erupt before 😀
The main fountaining stage has started.
Here is another camera link.
Already posted, but here it goes again: a link to many different cams:
Etna sure is going at it today!
Oh yes, really big fountains right now, the red glow visible in direct sunlight as well
maybe growing now? Great daylight views! Any better “Live-stream” cameras ?
Tremor at 177 (EBELZ) and 106 (ECPNZ) respectively. Greater than peak values last few times and one of the most powerful in this 15-month long series of paroxysms.
Now it’s at 186!
Now at 190 / 106
I don’t recall how large the set was that originally got me tracking “stress waves” up the Gulf of California. M 6.2 isn’t an itty bitty quake.
If I was correct in my line of reasoning then… there should be another bit of activity within a month or so, about 150 to 250 km further to the north along that system. It would keep doing this until it gets to the area of Yuha-Wells… then whatever happens, happens. At that point it turns into a gravel pit and you can’t really state what it’s going to do. The area is well fractured and many possible ways to dissipate/absorb the energy.
Question to all you seasoned/regular Etna watchers: is it my imagination or is this paroxysm XXL size?
I’m asking myself that very question.
There are some very rapid “flows” coming down the flank – I hesitate to call them pyroclastic. Could be lahar? Very white (steam) and certainly not lava (it doesn’t flow that quick)
Without exaggerating too much… That “flow” dropped half the height of the summit in something less than 4 mins
There was snow on the slopes below the new SE crater. What you see is lava spatter/flows reaching and melting that snow, turning it to steam. No sign of either pyroclastic flows or lahars (which I doubt occur at Etna).
VAAC Toulouse has it but no forcast maps yet issued. Seems rather large to me,
INFO SOURCE: INGV CATANIA, WEBCAM
AVIATION COLOUR CODE: NIL
ERUPTION DETAILS: SIGNIFICANT ASH CLOUD OBSERVED AT 1053Z
OBS VA DTG: 20120412/1053Z
OBS VA CLD: ASH NOT IDENTIFIABLE FM SATELLITE DATA.
WINDS SFC/FL100 W 25KT.
Last sentance is winds at Flight Level 100 (10,000 ft “standard at 1013 Hp / ISA”) are from West at 25 knots (12 m/s)
I think Boris is going to hate taking that well earned vacation.
It is the largest I have ever seen.
He should have left his camera set up so his daughter Ida could have taken some photos.
Hey, it is Boris daughter, I bet she is photographing, if she is not with daddy in Germany.
Yes and it has peaked by now. The largest and fastest.
Saw some big ones sometime around 2000-2002 (I forget exactly when but I remember coming home from either my GCSE or A Level exams and going straight on the computer to watch them)…… and I think this one might be bigger. Impressive.
And that would have been when it got active again.
Hell, am I looking at Etnatubo here or what.
when did Etna last cough up a 5 km ash column?
Wonder if this will be the first paroxysm that get a DIE-number attached to it.
Judging from column height and an estimate of 100 tons per second of ash it should be a DIE-2.
Etnatubo haha I like it!
Everything sounds better with the -tubo attached to it. 🙂
Hmm… Eyjafjallajökullatubo? Burfelldalekatubo?
Nah Henritubo, there was though a Eyjatubo moment
Eyjatubo? Alas too brief a name for my liking Carlatubo. 🙂
Tremor is starting to drop now.
Nice pyroclastic flow on Etnatreck cam 1.
Watching (doing mental practice for Mrs. Hekla) *whistles*
Once SHE blows, Mt Etna’s best like today’s are going to seem no more than a polite cough.
What pyroclastic flow? :p
The one that was on one here…
All I saw was snow being melted and turned into steam, Carl. There were three “plumes” counting from the top: 1) Eruption column, dark grey, 2) weak plume over lava flow, brownish grey, and 3) strong water vapour plume, white.
Yepp I know, and I have pic of 1 faltering and running downhill. There is also some melting done there, and that gave white steam, but you can see the difference.
I should clarify here, there was a lavaflow exactly as Henrik says, it is just that when the ash column failed it took the same road down.
And there it was over by the looks of it, the entire shebang stoped and the ash column droped down.
Take a look at cam 2 (Etna Guide/Etna Trekking) and tell me what you see please.
I see a failing ash column dropping down on the mountain as the heat the lofted it died out. And when the hot ash drops…
Here – http://www.facebook.com/photo.php?fbid=425768597449624&set=o.160531093975591&type=1&theater with Dr Boris Behncke’s comment:
“Boris Behncke: there were again the typical interactions between lava and snow, creating those phenomena looking like pyroclastic flows, though they are different and need to be named properly
Etna Trek 2 Looks like wisp of steam or smoke venting from the lower right side of the slope and drifting across and up?
I will post the pick of the ash column failure.
Wait a few minutes.
Both pyroclastic and lava flows. And also a lahars generated by both. Boris has explained that in other occasions. And huge phoenix clouds from the PFs!
My bad. Boris said that on FB, for this time, not exactly pyroclastic flows.
But you are right Renato.. We have had both PFs and lahars in recent paroxysms – this according to the man himself.
In Italiano: pyro-hydro-clastico!
Andy, I like it! It sounds as though Boris is moving away from earlier comments about PF flows forming during these events. Though Etna has had true PFs in the past during other eruptive phases. I remember asking him precisely this question some years ago.
“Boris Behncke That’s the thing we used to call “pyroclastic flows” lately, although we are beginning to understand they are not typical pyroclastic flows (that is, dry and hot) – these are very wet and less hot (though presumably still deadly) and probably at their base they are rather lahars (mudflows). These phenomena have never been accurately described in the scientific literature until 2011, and seem to be pretty common during high-rate lava effusion from snow- or glacier-covered basaltic or basaltic-andesitic volcanoes (e.g., Llaima, Kliuchevskoi …)”
OK, I claim copyright on “pyrohydroclastic flow” 😉
Good stuff Etna – first time I’ve caught a start-to-finish live. I’m impressed!
Same here! 😀
I say “pyro-avalance” (Blend of heavy-ash-laden-gases, hitting snow, turning it into steam, the added water content makes it more fluid and increasing downhill speed, when water dries out it settles as ash-sholes.) ????
And I have posted pics of it 🙂
New post with the failing ash column. I guess it is what Boris commented on. A heated ash column with a lot of steam in it that can not sustain its wait as it crashes down.