Nabro another Krakatoa? Nabro stops erupting.

This, is all speculation based purely on what little is known about Nabro in Africa.

Eruption cessation source:

www.irishweatheronline.com...

First a little short back story. Krakatoa. She erupted from one of her 3 major peaks, initially a violent explosive eruption with large flows. Then suddenly she went quiet. A cork of cooled rock sealed her now disturbed magma chamber off... later, all three peaks blew in one massive eruption. This is a repeating process it seems, Krakatoa apparently has a history of explosive eruptions of varying sizes. The primary factor in Krakatoa's eruption was an initial basalt magma, then rhyolite magma for the final explosion.

Now back to Nabro. Nabro is part of a caldera system like Krakatoa was...with the same kind of magma...

Basalt, trachyte and rhyolite are among the rock types which Nabro has produced as lava flows and pyroclastics.

From Wiki, sourced from www.volcano.si.edu...

While we don't know the specifics, like I said, this is speculation based on information I can find...there is this.

The other day, this was Nabro.
Yesterday

Today it has stopped erupting suddenly...like Krakatoa did.
Today

So we have established, A: Similar magma types, B: Both erupted violently, then went quiet before the main event (for Krakatoa so far, at least.)

EDIT: Adding from one of my reply posts for clarification purposes for future readers.

In reply to Krakatoa and Nabro being Rift vs Subduction zoned volcanoes and thus different formation types.
Clarification: While the volcanoes formed under different circumstances, we know both have similar magma, both are explosive, and both are large. The Nabro eruption shows large quantities of water vapor in it's plume. I think, while formation is different, the end product might be similar.

Now the final thing.

This is Nabro in January 2011.


If you go to Google Earth you can see ALL the volcanoes in this system have large calderas from major, explosive eruptions. The current vent that we just saw actively, did not produce such a crator. It erupted and has now, seemingly, plugged itself.

With a disturbed magma chamber, and a plugged vent - if there is still pressure in the chamber, then its possible we will see another explosive eruption... and based only on the geological sat photos, it seems that this volcano has had major eruptions in the past.

I'm not ringing a bell here, there is no need for panic. I am posting this purely as a geological interest, and I want other people to give me their own opinions. A geologist friend said, without field data and historic eruption information he can't tell me one way or the other. So I decided to simply share this.

Again, I am posting this as a geology intrigue, not as "DOOMSDAY OMG" post. This is simply an interest event and I feel we seriously need to study the situation there. Without more information we will not know. Simple as that.

S&F!

Great correlation... this could get very interesting, thanks for pointing this out.

I hope it doesn't end like Krakatoa, which killed a lot of people and made most of the planet dark.

~Namaste

I'm tempted to point out that Nabro and Krakatoa formed under very different conditions - one in a rift zone where a continent is starting to break up, the other an island arc formed by a subduction zone where one plate is pushing under another - and so we shoudn't really try and draw analogy.

But I'm then reminded that in the early days of the break up of Laurasia - when America split from NW Europe - there were some very major eruptions in what is now Scotland.

So I guess at some point Nabro and the surrounding volcanoes could well produce some very major eruptions. And the facts presented here are certainly interesting.

Probaby won't happen. But we can't write it off ......

Edit: to say S&F for some rational thinking and refusal to succumb to the usual scaremongering tactics

reply to post by Essan


Well, I thought the same - but those massive calderas only form when there's large explosions*, so at some point in the past it DID have huge eruptions...question is, will it ever again? Maybe unlikely, but I still think it prudent to keep an eye on it.

*I could be wrong, a large eruption, with empty chamber, and sub-sequence collapse of dome into empty chamber is possible too I think. Apologies. I should of checked before running my mouth.

How might a rift volcano explode like Krakatoa? Well, if there is up-lift from pulling apart, and enough pressure builds beneath a weakened point...

We've had surprises before!

Clarification: While the volcanoes formed under different circumstances, we know both have similar magma, both are explosive, and both are large. The Nabro eruption shows large quantities of water vapor in it's plume. I think, while formation is different, the end product might be similar.

reply to post by Foxe


Good point

We should at the least be prepared for the possibility. Though Fortunately I don't think a major eruption there would be too disruptive - it's not quite so near the equator as Krakatoa or Tamboro and fallout would not be global, only affecting the N Hemisphere ......

...... hmmmm ......

reply to post by Essan


As I corrected in my post - I could be wrong on those calderas, they could be collapses and not explosions... honestly they look explosive formed, and the current/most recent eruption + those from nearby are explosive... so yeah. It could be either-or?

I do know that if would likely mess up flights! Hah...these volcanoes are going to ruin the air business, aren't they.

I can't believe this has not gotten more attention....especially since you put so much thought into it. I'll be watching this! S&F for you.

reply to post by StealthyKat


Thanks Kat.

I'm sure plenty of people are reading it, its alright if no one replies. I would be pleased as pie though if I could get some feedback from Puter or someone of equal knowledge.

First may I say that I don't believe it has stopped. There is still some detectable output on the EUMETSAT Ash pictures.

This is the latest one I have @ 21:00 UTC

[atsimg]http://files.abovetopsecret.com/images/member/9ae32ba53796.jpg[/atsimg]

That still seems to be showing something.

First may I say that this is a good thread, but it needs input from Aromaz rather than me. I am more on the earthquake side of things and cannot speak authoritatively about volcanoes whereas he can.

I think as you and others have pointed out there is a difference, actually a very big difference, between the two volcanoes.

Not least is the fact that Krakatau has a history whereas Nabro does not, at least not in the Holcene. Also, by comparison to some other eruptions Nabro was not really a violent eruption. Three volcanoes went to form the caldera of Krakatau, but Nabro has it's own caldera as do the others so whilst they are probably all connected in one system I can't see an 80km wide caldera being formed. (I certainly hope not)

Having said that your idea is not without merit. I shall u2u Aromaz to take a look.

I will see if I can sequence the output for today as I certainly do not trust the Toulouse VAAC to get anything right, after all they swore bind it was Dubbi.

reply to post by PuterMan


Thanks Puter. That is exactly why I didn't want to get panic-y. I'd appreciate the other to look into it as well.

Most importantly, as I should of said in the first post, I don't think this would be a severe, Krakatoa scale eruption - I meant - it was plugging up possible (apparently not thanks to your information so far.) and could lead to a more violent eruption in general - or force a vent to close to another system and bring about a chain reaction (as was feared with the Eyjafjallajökull vent and Katla.)

My primary reason for this thread was to put more thought into Nabro. Beyond general awareness like in Volcano Watch 2011 (Figured opening a debate on a specific volcano was worth its own thread.)

At best, such an interesting eruption needs more attention than its getting (Media and otherwise) for the sake of knowledge.

Thanks for your time.
o7

(Drat, past 4 hour edit time...really wanted to add to the fact I meant Krakatoa-like, not Krakatoa-strength.)

I'll add to this a bit.

Nabro is more basaltic which is evidenced by the long lava flows and this link will explain that for you:

bigthink.com...

Krakatoa's eruption, as big as it was, can only be caused by a massive amount of rhyolite and this link will show you how it may be different from Nabro

hvo.wr.usgs.gov...

Not saying your theory isn't correct but it appears there are very different circumstances going on with these two. They both have mixes of the magma types but one seems to have been more rhyolite while the other seems to be more basaltic.

reply to post by PuterMan


I'd just like to add, remember we're talking about Krakatoa here, they didn't have the technology to study volcanoes as in-depth as we can today, so likely it appeared that it was inactive, much like today's Nabro, but deep underground, it may be showing signs of movement/unrest.

Originally posted by SonOfTheLawOfOne
S&F!

Great correlation... this could get very interesting, thanks for pointing this out.

I hope it doesn't end like Krakatoa, which killed a lot of people and made most of the planet dark.

~Namaste

I don't think to many people live around this area. Also Krakatoa killed most with the Tsunami it caused on the other near by Island. What was shocking about Krakatoa is that it was so loud when it exploded it made everyone deaf on the near by islands for awhile. People were bleeding out of they're ears. If we hear a large explosion then at least we will have a clue what happened though.

reply to post by Foxe


As promised here is a GIF of what I can see from the EUMETSAT Ash images. It may take a while to get going as it is nearly 5MB

It can be clearly seen that 'something' is happening. It may just be water vapour (note that it fades as the other clouds fade as the heat builds), I can't say but as far as I am concerned that has NOT stopped yet even though just at this time it may not be erupting ash.

[atsimg]http://files.abovetopsecret.com/images/member/dfb759f5fadb.gif[/atsimg]

ETA: Look under the word 'may' about 1/2 inch down if you can't see it. By the way thos images are right up todate as of posting. 22:00 UTC last night to 07:00 UTC today and it is now 08:57 UTC. Next image due in about 10 minutes or so.

The only way to accurately assess the nature of this eruptive series is to have highly sensitive tilt-meters on the ground around the volcano and on the volcano itself.

It's safe to say that if your theory has any truth in it, we'd see an element of plastic behaviour taking place in the formations nearby. An intrusion of the magnitude you describe, as well as the pressure required, would create a distinct pattern of distortions easily noticeable with the right equipment.

The biggest problem, as already noted, is the remote location of this volcano and the fact it hasn't been studied in detail. Let's hope it ISN'T a Krakatoan style eruption building up, and that if it has to go, the plug shatters and creates a Plinian eruption....

The Rev.

For the geologically, volcanologically and petrologically clueless amongst our readers, Rhyolitic magma is much thicker and less viscous than the highly plastic Basaltic magma.

When Rhyolitic magma erupts past the surface and cools, it often looks like a flaky, powdery substance, that is very hard and brittle. As anyone who lives in Hawaii will state, Basaltic magma / lava often looks something like tarmac - and behaves in the same way.

Imagine then, trying to explode something hard and brittle, versus something that will stretch and accommodate the pressures relatively well.... Karaktoa versus Mauna Loa for example... this is the fundamental difference between 'effusive' eruiptions, and 'explosive' eruptions.

Just so you all know.

The Rev.

ATS: Where even the stoppage of a natural disaster portends doom.

Imo though, it's far to difficult to judge when even a regular volcano is going to erupt - let alone a special case like this. I wouldn't move out of country yet, it might end up being ok.

i flagged you...then unflagged you...to only flag you again, rince and repeat.

Because flagging you feels so good....

Very solid OP

GREAT post, thanks for the info.


No need to over analyze this, THAT IS WHAT VOLCANOES DO

They erupt for a while ...

They create a huge mess ...

The mess rolls back, caves in, and plugs it up ...

Then the pressure builds and EXPLODES ...

AND THEN IT STARTS ALL OVER AGAIN

reply to post by The Revenant

It's safe to say that if your theory has any truth in it, we'd see an element of plastic behaviour taking place in the formations nearby. An intrusion of the magnitude you describe, as well as the pressure required, would create a distinct pattern of distortions easily noticeable with the right equipment.

Very true, but the problem is that this is a very remote area. There is no instrumentation, and there is no communication either so even if you did place instruments they could not send back data unless they had a functioning satellite link.

You also have to realise that it can take days just to get to the region of Nabro so there is no way anyone would know if there was plastic behaviour taking place of not.

Oh and by the way I do realise you said that, I just wanted to reinforce the point.