Category Archives: Eruption

The count of Etna paroxysms in February 2013 now stands at 4 (and NTV Riddle)

This screenshot shows the first sight i got when i woke up this morning. Bruce Stout had been watching the event from the time it started and had left comments on VC which made me aware of what is going on. Etna changed its behavior the last days and displayed a 4th paroxysm today early in the morning after being active twice yesterday.

INGV analysed the paroxysms of the 20 in this articles in Italian and English. You can most likely expect a new report on todays events at http://www.ct.ingv.it/ a little later. Dr. Boris Behncke made some comments over at Eruptions where Erik had been writing a post on Etnas behavior too yesterday:

http://www.wired.com/wiredscience/2013/02/etnas-explosive-last-three-days/#comment-806546971

Yesterday someone zoomed in one Radiostudio7 cam and so i could take nice screenshots…

This picture was created out of the best screenshots i got of the Radiostudio7 cam yesterday.

http://www.radiostudio7.it/webcam.asp?web=7&id=7

Claude Grandpey reported live on his blog yesterday.

Check the lower right side of this image. I have not seen that spot before!

I´d like to paste some of the comments into this post to start a discussion:

Bruce noticed that same lava break-out feature has reappeared:
http://i40.photobucket.com/albums/e211/NoEnz/Bildschirmfoto2013-02-21um061250_zpsa0fbc1d1.png but Newby could be assured that no people are in danger because the ava flows down into an uninhabitet valley called Valle del Bove.

Bruce Stout says: February 21, 2013: Good morning, everyone, (yawn), oh look, Etna is at it again (no. 4) instant wake-up call.

Initial thoughts on Etna. A while ago I postulated that the periodicity in Etna’s paroxysms was caused by a steady magma feed into a piston like chamber with a narrow opening to the surface (this piston might be nothing more than the conduit itself). In this case the mechanism would be that magma enters the piston, starts to degass due to drop in pressure and slowly fills the piston until the pressure and volume was high enough to clear out the flimsy plug left by the last event. The built-up pressure in the piston coupled with rising levels of exsolution of gases leads to the fountaining as the piston empties itself. Rinse and repeat.

Now, if this is correct, why the sudden increase in the frequency of these paroxysms? Two possibilities come to mind: Faster rate of magma feed from below or a smaller piston.
Working in favor of the latter, is that the volumes of these paroxysms seem to be smaller than the previous series (though I am flying on the seat of my pants on this one, just guessing from the videos/webcams). It is most likely a combination of both faster feed and a smaller piston volume in the upper conduit. If higher feed, we might see a flank eruption at some stage which Boris once said often follows such series of paroxysms.
Just some random thoughts put here for discussion…
February 21, 2013 at 05:04

Well, bang goes that theory… this paroxysm is back to the old levels:
http://i40.photobucket.com/albums/e211/NoEnz/Bildschirmfoto2013-02-21um055948_zps359e23dd.png

Webcams are offering some very atmospheric shots as the wind is blowing the cloud towards the cam, obscuring the vent:
http://i40.photobucket.com/albums/e211/NoEnz/Bildschirmfoto2013-02-21um052759_zpsa67f8318.png

Spica: Ok the tremor is down again. The event seems to be over.
Bruce took a screenshot of the tremor being at 121 i saw it at 123 and when you check the graph now it shows that is was never as high as with the first paroxysm on the 19th. Can anyone explain this to me, this is not the first time i saw this behavior of the tremor graphs and i never understood it.

Boris mentioned on eruptions that it is not the first time Etna shows many paroxysm. In 2000 it started paroxysms in January and till late August the count ran up to 66 ! of those explosive events. I am bringing the webcam list over again so you have a chance to watch the show on your own.
Etna webcams:

One more screenshot for all who missed the show!

taken from the Lave cam: http://www.lave-volcans.eu/webcams_etna.php?numero=2

Name those Volcanoes Riddle

4 volcanoes 4 points

No 1 – Does it serve as a warning beacon for ocean going ships? Its nickname includes the name of an ocean. SOLVED
No 2 – This volcanic island’s artifacts/treasures, specifically A & A,  can be found in both the B M and the L. A & A are the names of ancient statues. SOLVED
No 3 – Here the salty craters hold a current ‘known’ subaerial world record. SOLVED
No 4 – During a warm, summer month in 2012 its summit displayed an historic ‘first’. Icelandic volcano. SOLVED

Spica

2 Etna paroxysms

Etna has been providing a show again yesterday 19.2. and early this morning 20.2. Etna seems to love night time action and most of us Europeans missed it, so I am trying to provide a short summary of the paroxysms. When I woke up and checked the cams around 7 a.m. on the 19th. , the image above was all I could grab.

EBELZ
The up-to-date tremor plot can be found at http://www.ct.ingv.it/index.php?option=com_wrapper&view=wrapper&Itemid=201&lang=it
Only EBELZ shows acurate measurements. ECBNZ only hickuped a few times the last week and if it continues operating like lately, there will only be a black page soon.

The definition of paroxysm is a short outburst of action. All of Etna´s actions in the last 2 years were paroxysms and no longer lasting eruptions.

2 webcam screenshots (not from the same cam) taken on the 19th and the 20th. Notice that there is fresh black ash to the right on the second image. Were there some other tiny little vents active closeby to the main crater?

Here the best video, I have seen so far, by Klaus Dorschfeldt, it was first mentioned on Erik´s blog and also brought over to VC  by KarenZ.

Even a pyroclastic flow is to be seen. May I mention that I find the “erupting” logo on the lower right side a tiny little bit disturbing?

The paroxysm of 19.2. was worth being mentioned by CBS News.
Turi Caggegi has some new images from February 19 and 20 on Flickr.

Only a few articles can be found online:

This link leads to Etnaboris Flickr images but he always writes a long description to his images and so this provides a summary of the action of the last 2 days.
Claude Grandpey reported: http://volcans.blogs-de-voyage.fr/2013/02/20/etna-sicile-italie-306/
The Watchers have 2 webcam screenshots one of which is a screenshot of the thermal cam. When I checked that cam only an afterglow was visible.

Emot0114
Some usefull links for our readers to watch the action on Etna:
Etna webcams:

A Springer link about the enormous amount of CO2 emitted by Etna per year. 25 Mt/y !!!

Update: While I was writing this post ( I guess) Dr. Boris Behncke updated the IGNV site.

Here is the activity report for Etna and Stromboli for the 19th with many beautiful images,
And the same for the 20th which should be updated again soon as the article anounces.

SPICA

Update:

The Decade Volcano Programme

Fig.1 The dead of Herculaneum, burnt to death by 800-centigree hot pyroclastic flows from Vesuvius AD 79 (O Louis Mazzatenta, National Geographic)

Fig.1 The dead of Herculaneum, burnt to death by 800-centigree hot pyroclastic flows from Vesuvius AD 79 (O Louis Mazzatenta, National Geographic)

The volcanic eruptions of Mount St Helens in 1980 and Nevado del Ruiz in 1985 made the general public aware of the dangers of co-existing with a large and potentially lethal volcano. It doesn’t take much imagination to see the possibilities of a lateral St Helens-type blast on a population of a great city as unaware of the hazard as the unfortunate citizens of Armero, Colombia. Blasts from the past such as Vesuvius 79 AD eruption that obliterated the large Roman cities of Pompei and Herculaneum or the 1902 eruption of Mount Pelée on Martinique, that completely destroyed the town of St Pierre, leaving only two survivors out of a population of some 22,000, served to reinforce the message. With human populations world-wide soaring, it is inevitable that humans will settle closer to potentially active volcanoes in ever-increasing densities. As a result, more human beings than ever are at risk from volcanic eruptions.

With this in mind, the HYPERLINK “http://en.wikipedia.org/wiki/International_Association_of_Volcanology_and_Chemistry_of_the_Earth%27s_Interior” \o “International Association of Volcanology and Chemistry of the Earth’s Interior”  (IAVCEI) set out to identify volcanoes that had a history of large, potentially destructive eruptions and were located close to high-density populations. As the project was initiated as part of the United Nations-sponsored International Decade for Natural Disaster Reduction, hence the name Decade Volcano, it was hoped that the United Nations would fund the programme the aims of which was to identify the major strengths and weaknesses of current hazard management and contingency plans at each volcano, and how to address the weaknesses identified.

Fig. 2 The UN General Assembly. It was ultimately here support for the Decade Volcano programme must be obtained, not at some faculty. (Marty Lederhandler, Associated Press)

Fig. 2 The UN General Assembly. It was ultimately here support for the Decade Volcano programme must be obtained, not at some faculty. (Marty Lederhandler, Associated Press)

It must be realised that in a highly politicised world, decisions are rarely based on scientific grounds, but on what is politically feasible. Hence the volcanoes chosen had to have a broad appeal, geopolitical as well as demographic, to the representative body that was to grant the funding. But in order to achieve at least a semblance to a scientifically motivated choice, the volcanoes chosen had to threaten tens of thousands of people with at least two of the following volcanic hazards – lava dome collapse, pyroclastic flows, lava flows, lahars, tephra fall or volcanic edifice instability. Furthermore, the volcano had to have been recently geologically active. As a sop to the UN representatives, who in turn would have to have the sanction of their masters at home, any volcano chosen had to be politically and physically accessible for study and there must also be local support for the work.

In the end, the UN did not undertake to support the programme, and funding had to be obtained elsewhere. Where there is a national body responsible for volcanologic research and monitoring such as in the USA, Italy, Mexico or Colombia, this organisation has assumed responsibility for the volcano or volcanoes that naturally fall under their aegis. The European Union supports research and monitoring at European volcanoes whereas some of its member countries, France and Germany, have undertaken to support the work of Indonesian authorities at the same time giving French and German volcanologists access to research at active volcanoes.

Fig. 3 Koryaksky volcano overlooking Petropavlovsk’s 180,000 inhabitants (Wikimedia)

Fig. 3 Koryaksky volcano overlooking Petropavlovsk’s 180,000 inhabitants (Wikimedia)

The 16 volcanoes given status as Decade Volcanoes, with the (main) human habitations threatened given in brackets, are:

USA – Mount Rainier (Seattle, Washington) and Mauna Loa (Hawaii)
Japan – Sakurajima in the Aira caldera (Kagoshima and Kirishima) and Unsen (Unsen and Nagasaki)
Russia – Avachinsky and Koryaksky (Petropavlovsk, Kamchatka)
Italy – Vesuvius (Naples) and Etna (Catania)
Greece – Santorini, a.k.a. Thera (Aegean Islands)
Spain – Teide (Canaries, holiday paradise of Europe)
Mexico – Colima (Colima, Manzanillo)
Colombia – Galeras (Pasto)
Phillipines – Taal (Manilla)
Guatemala – Santa Maria/Santiaguito (Quezaltenango)
Indonesia, Java – Merapi (Yogyakarta)
Democratic Republic of Congo – Nyiragongo (Goma)
Papau New Guinea – Ulawun (???)

While no one doubts that given a possible or hypothetical worst-case scenario, these volcanoes pose a serious threat to nearby human settlements, it’s quite obvious that politics has been a main factor in their selection as Decade Volcanoes. The financially and politically influential USA, Russia and Japan have each been assigned two with four to the equally politically and economically influential Europe, while the large Hispanic contingent of nations accounts for no less than five of the sixteen.

Nevertheless, it is a start and a good one too. The programme has led to a better understanding of the volcanic hazards and in one case, at Etna in 1992, measures were taken on the advice of IAVCEI (International Association of Volcanology and Chemistry of the Earth’s Interior) that eventually prevented a lava flow from reaching a town. Scientists and civil protection authorities have learnt to cooperate as with the very nasty eruption of Merapi in 2010, without which the death toll would undoubtedly have been much higher. Awareness of volcanic hazards from volcanoes not on the list has been heightened as well. A summary of the advances and achievements brought by the first ten years of the programme can be found at “http://www.sveurop.org/gb/articles/articles/decade.htm”  Directly below, followers of this blog may be surprised, or not as the case may be, to learn that our old friend Nemesio M. Pérez compiled the final report of the IAVCEI meeting in Teneriffe, 2010.

Fig. 4 The 2334 m high Ulawun stratovolcano, Papau New Guinea (listspress)

Fig. 4 The 2334 m high Ulawun stratovolcano, Papau New Guinea (listspress)

But it cannot be claimed that all the Decade Volcanoes represent the 16 volcanic centers most dangerous to human populations, nor that the efforts are directed where they are most needed. Let us look at Ulawun, Papau New Guinea as one example! Ulawun, a 2334 meter high stratovolcano, is the tallest volcano of the Bismarck Archipelago chain and one of the most active volcanoes in Papua New Guinea. According to John Seach, it is composed of lava flows interbedded with tephra and erupts basalt and andesite through Strombolian and Pelean eruptions. Thus the main danger to humans comes from the pyroclastic flows associated with Pelean eruptions, the other Decade criteria met are those of tephra fall and structural failure. John Seach reports that the 1980 eruption resulted in an 18 km high eruption column that devastated some 20 square kilometres and claims that structural collapse could potentially lay waste to an area hundreds of square kilometres. That is an area with a radius of about eight to ten kilometres.

But is Ulawun really such a highly dangerous volcano? First of all, as far as I can tell from maps and satellite images, there are few human habitations within the danger zone. Second, it erupts basalt and andesite, neither of which are associated with particularly devastating eruptions. Basalts erupt effusively as at Hawaii or semi-explosively as at Etna. Andesites predominantly erupt explosively, but rarely result in a high VEI as both volume-wise and explositivity-wise they are small to medium. Third, Ulawun erupts regularly, 34 eruptions over the past hundred years with most assigned a VEI of 1, 2 or 3 with a single VEI 4. While this is impressive and a constant reminder to the locals that theirs is a dangerous volcano, the regular eruptions prevent the build-up of a much larger eruption – and also inhibits the build-up of a large human population on its fertile slopes.Simpson Harbour Rabul USAF
Let’s now move our examining eye some 200 km to the NW of Ulawun! There we find Rabaul, the city of WW II fame fought over by the Japanese and Americans for its superb anchorages. Up until 1994, Rabaul was the provincial capital with a population of some 17,000 inhabitants. On September 19th 1994, the Tavurvur and Vulcan stratovolcanoes erupted simultaneously which destroyed the town as had happened previously in 1937. Fortunately, no more than five people were killed this time against 500 on the previous occasion. Today, the provincial capital has moved to Kokopo, a scant 20 km away, but Rabaul is slowly being rebuilt as happened after its 1937 destruction.

Why is Rabaul then, to borrow a phrase from Carl, such an ill-begotten piece of real estate? The reason for its superb anchorage is that it is a submerged caldera, 8 by 14 km wide. The town is located on the rim of the caldera and there are no less than eight vents of which four are stratovolcanoes such as the already named Tavurvur and Vulcan. Just to make certain of the town’s eventual destruction, the spit of land on which Rabaul is situated is not only the edge of the Rabaul caldera. A scant three kilometres due north lies the equally submerged Tavui caldera, source of the 5100 BC Raluan rhyolitic ignimbrite, an eruption listed as producing 4.0  ±  1.0  x  109 m3 of tephra.

Fig. 6 Map of the Rabaul Caldera (USGS)

Fig. 6 Map of the Rabaul Caldera (USGS)

No doubt there are other, and better examples of volcanoes that ought to have been Decade Volcanoes instead of some of the obviously less than well-chosen current ones, but it cannot be denied that the project has realised its goals and done so very well indeed! The context of its genesis, well before the advent of the world-wide web with its instantly accessible webcams and monitoring equipment, has to be taken into account as well. In the final analysis, the Decade Volcano programme has to be regarded as being highly successful.

HENRIK

Suggested reading:

HYPERLINKS :

http://upload.wikimedia.org/wikipedia/commons/4/42/WikiReader_Decade_Volcanoes.pdf

http://www.iavcei.org/” http://www.iavcei.org/

http://www.sveurop.org/gb/articles/articles/decade.htm

http://www.geo.mtu.edu/volcanoes/rabaul/rabaul.usgs.html

Apocalypsathon; Post 21/12/12 Appeal…

I think Tyler Mannison found this one...

I think Tyler Mannison found this one…

Send your urgent and much needed donations for those poor unfortunate endotheworlders who were not wiped out (they must be devastated) to schteve’sschwissbanking.ch

Please spare a thought and a dime for those not raptured up to heaven in the recent non- apocalypse; give generously, it’s nearly christmas after all…

since this didn't happen everywhere all at once...

Since this didn’t happen everywhere all at once…

I intend to set up a refuge high in the hills of La Gomera with a nice piece of (terraced) land and a look out tower; we’ll charge post 2012ers top- whack to come and contemplate… Me n’ Lizzie will be there most of the year looking after the goats and generally taking care of the place (and going for long walks and jaunts to El Hierro and stuff.) So once again Volcanocafers please dig deep for this very worthy cause…

Somewhere like this, Pico del Teide is in the distance...

Somewhere like this, Pico del Teide is in the distance…

http://upload.wikimedia.org/wikipedia/commons/thumb/a/a5/La_Gomera_1.jpg/1280px-La_Gomera_1.jpg

But seriously, and since we are still here; a genuine appeal (and some of my highlights):

This rather special place was started by Carl and Ursula after a group Volcanoholics decided they wanted their own place with their own rules… Those that wanted to go multidisciniplary, collaborative and friendly came here and (boy!) the discussion was, and still is, far ranging… The Welcome page and blog rules are here:

http://volcanocafe.wordpress.com/2011/11/15/volcano-cafe/

The average post rate is ~ one every 3 days, (that includes before and after Carl statistics…) some volcanoblogs manage more, but usually these are brief updates. What we get here are crafted pieces, made by amateurs in their spare time…

The hit rate is around ~150 visits per hour; this doesn’t include dragon visits…

I won’t lie to you; a blogpost can be quite a bit of work, depending on your skills… Carl once mentioned that he could write a 1200 word opera review in 20 minutes, and Geolurking seems to be able to get something revolutionary on tectonics done in only slightly more time…

Birgit deserves her own paragraph; she can research, compile, edit, post and get an intelligent layman up to speed on a particular subject in less time than it takes a crocodile to swallow an unwary victim!!!

Me? I’m at the other end of the scale; maybe 20 hours work on Teneguia Technicalities and Context, but that did include editing with wordpress which was a first for me… Don’t let me scare you, I can be quite ambitious…

I am asking everyone to keep the posts coming; think of it as an extended comment and you will do fine…

This one's for our resident geologist...

This one’s for our resident geologist… The little engine that could x

http://upload.wikimedia.org/wikipedia/commons/thumb/d/d2/Snowdon_Mountain_Railway_No_6.jpg/1280px-Snowdon_Mountain_Railway_No_6.jpg

Visits to volcanoes “a la Ukviggen” are always popular; (Mount Snowdon anyone? The narrow gauge, rack and pinion railway is the only one of it’s kind in the UK.) as are summaries of your favorites; (Karenz on Sakurajima is a very good example.) and memories of eruptions that were special to you; (Bobbi’s piece on Redoubt is a classic, and don’t forget Newby’s uncle on Erebus.)

Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula April 21, 1990 (R. Clucas)

Ascending eruption cloud from Redoubt Volcano as viewed to the west from the Kenai Peninsula April 21, 1990 (R. Clucas)

For the more ambitious how about an original piece of research? (Irpsit wrote a fascinating series about a big hole!!!) Controversial stuff is great, got an alternate theory? (Peter Cobbold on El Hierro is excellent.) What about something inter- disciplinary? (Diana Barnes on Scheeps helping to revive volcanic badlands is wonderful!) Technicalities more your bag? (Wagabond on marine seimic sounding; great insights.) Plotters, hows about “beefing up” a special plot? (Plotting for Beginners 2 may get done one day, but feel free to jump in!!!)

One of Birgit's SEM images of material from El Hierro

One of Birgit’s awesome SEM images of material from El Hierro…

If none of these inspire how about something outrageously off topic for the Scheeepy Dalek?

Nothing is like the smell of a Motorcade in Depresneyville in the morning. Remember that when people shoot at you, they just wish to greet you welcome to Ukraine.

Nothing is like the smell of a Motorcade in Depresneyville in the morning. Remember that when people shoot at you, they just wish to greet you welcome to Ukraine.

So please, go and do yr research, track down the info on yr chosen subject and write something up… Include the standard Volcanocafe disclaimer and a reasonable list of references; and you’re done…

Posts are best submitted as plain text word documents; attached to an email. Pictures should be separately/ individually attached; most formats are fine but please no psd, crw or nef (they are too big and probably not supported by WP either; they need to be converted first). Jpg, gif, png, tiff are commonly supported formats and will do well.

However; when I asked Sissel about this, she said: “Just send it, I will edit what is neccessary!” (another inspirational blogger; remember The Little Prince?)

Have you ever made a comment that you (later) wished you’d saved for a guestpost? Then we want to hear from you; (give us as much detail as possible: approx dates, subject, etc. and we will go digging) dragons can search all 70,000 comments and extract that moment of inspiration…

My top tip (I know it’s environmentally unfriendly) is to print out the papers that you are really interested in; the references for yr article; that kinda thing…

Posts and comments are the lifeblood of the blog, there are (almost) no stupid questions or statements.

So there you have it, no more excuses for not handing in your homework!!!

With Love and Respect,

Schteve x

Links to inspirational articles:

Lost Weekend…

Photograph from Wikipemedia Commons. Menengai Caldera in Kenya, one of the largest calderas on the planet.

How to kill a weekend.

As some of you have observed, last week I asked for anyone running across a caldera size and eruption volume to give me a quick shout here on the forums. Ostensibly, I was going to compile a spreadsheet in order to look at Hagstrum’s hotspot list compared to large caldera locations. Despite Carl’s disdain for the Antipode Impact idea, I think Hagstrum’s hotspot list is still pretty good, and it collates several other lists and weeds out some of the less than accepted ones.

While trudging through the calderas that were readily supplied, grabbing what info I could and trying to stay focused on DRE, the question of DRE again came up again in discussions. It wasn’t an actual argument or disagreement, but it did give me enough doubt in my data to seek other sources. Along the way, I found “Sulfur dioxide initiates global climate change in four ways” by Peter L. Ward. Well, to be truthful, I didn’t find that first, I found his table that supports his paper. I had to dig around to find the paper. I HIGHLY recommend the table. It is awesome. While the focus is on SO2 and climate change, they include the names of the tephra deposits that go with specific eruptions. Not all, but quite a few.

From his table, and with the re-worked VolcanoCafe user provided data, I came up with this (distraction#1) :

The first thing I would like to point out, is that it’s a log-log plot. The formula is a bit cantankerous to work with in Excel or on a calculator. (uses 10 raised to a power from a function that then has a logarithm in it.) The log-log plot was the only way to make it come out halfway usable. This formula was derived with DPlot, and in order to minimize the sigma fight (which I lost, quite readily) I left the individual points in place so that you can see just how far the estimate can be off. In one incarnation, I came up with the estimated value being within 0.77 of the actual value, 75% of the time. At this point I needed a beer and would continue later.

Moving back to the plot, and poking around in the text of the paper, I found that Professor Yukio Hayakawa of Gunma University (Japan) had compiled a list of large eruptions covering the last 2000 years. I had to go find that. Unfortunately, the list cuts off at 1999 with the eruption of Hudson in Chile. Distraction #2 involved updating the list with everything that happened since. While using his calculation of eruption magnitude, I decided to look back at how some of the calculations compared to fresher data from GVP. The paper uses M=log(m) -7, where m is the erupted mass in kg.

That’s actually a pretty handy formula. It sort of tracks with the VEI range, (but it’s not VEI, that’s different) Eyjafjallajökull comes in at 4.62, Merapi at 4.55, and Sarychev Peak at 5.04 when using GVP combined lava and tephra (DRE) volumes.

Photograph from Wikimedia Commons. The Somma caldera of Mt Aso in Japan.

I did find a problem with the data though… it wasn’t lining up with GVP info very well. In general, it was running 1.13 times the Hayakawa data when redone with GVP info. Then I ran into the problem of GVP not having anything more than a guesstimate for the VEI of some of the volcanoes with no tephra or magma volumes listed. (and these were pretty recent eruptions) Since Hayakawa used a lower cutoff of M=3.8, anything less than a VEI-4 would not get that high. (VEI=3 yeilds an M of 3.43). Ehh… give up and go find something to gnaw on. I did find out that my stepson had retribution against the Pelicans. I had skipped the King Mackerel fishing since I was “in the groove” with the data. The bait fish they were using had a tendency to attract the Pelicans attention but was so swift that it would be gone by the time the bird got to it.

Referring to Carl’s “Did you notice the erupting Supervolcano?” post, you will note that in the reference, it doesn’t state what the size of the Tondano Caldera eruption was. Being focused primarily on the geothermal energy capability of the system, that is understandable. Using the outline from Figure 5 of the paper, and applying our handy formula, we can get a ballpark estimate of how much “stuff” was involved. At roughly 30km by 9km, it comes in at 197km³… give or take. Solid VEI-7, but the calculation has a sigma of 351km³ so it could quite easily have been large enough to be withing spitting distance of VEI-8. (900km³ is within 2 sigma, and VEI-8 is 1000km³) 

[Editors remark (Carl): I actually was a bit more devious than that. For this caldera I have a bit more data. Through drill core samples I know how much of the caldera is infilled with original ash and later ash. That gave me the actual depth of the original caldera bottom. One should recognize the difference between a subsided caldera and a blow out large caldera event. The first one gently drops with lost material, the other ejects more material due to explosion, in this case when the ocean hit the magma inside the magma chamber. I then calculated the amount of DRE by size. To get a low enough number I did not assume that there was anything ontop, ie. that the volcano was flat with the surrounding landscape. I then got a 918 km^3 of ejected DRE. Size is not everything as I discovered, depth is equally important. Add a couple of the known active volcanoes before the large caldera event and you are comfortably at the 1000 cubic range for a comparatively small caldera. I then did a sanity check against known ash depths for the layer across distance, and fount it to be within the ballpark.]

Okay, back to the data. In 2009, Deligne, Coles, and Sparks put out a paper entitled “Recurrence rates of large explosive volcanic eruptions”. Yet another kick arse piece of work. In it, they use Extreme Value Theory to attack the problem of recurrence rates of large eruptions. Now that is something that I can appreciate. Extreme Value Theory deals with the failings of the Gaussian curve… out there in the tail, the realm of the infamous Black Swan that I am always yammering about exists. I have to go back and read that paper. Anyway, they mentioned Hayakawa’s list, and then using those methods, took the list back to the last 10000 years. Hmm… what can we do with that? I have the Greenland Temperature from the ice core data available, so I plotted it. It didn’t look that interesting until I ran an integral of the M value, then detrended it. That brings out the relative change in the sum that is going on without the actual data trend obscuring it. Plotted against the temperature, it look… “interesting”

There are a couple of peaks that seem coincidental, but for the most part, not a flipping thing there. I found it interesting that there was a peak in activity about 3527 BC and over all, volcanic activity has been declining ever since. I don’t know why that is. That’s just what it looks like. Being a glutton for punishment, and since it was “just sitting there,” I ran a couple of correlation routines on it to see if anything was present, but not obvious. Pearon’s correlation coefficient of 0.0111. Okay, I didn’t really expect a linear correlation. Spearman’s rho is supposed to be able to detect non-linear relationships, and I expected a higher score. I got 0.0017. What? It’s worse? “Wow.”

I have, on this computer, a program called “Formulize” by Eureqa. It’s free, unless you want to use a server farm. You can set it up and run it on your on PC and it will churn through whatever data you feed it and try to find a formula that relates the data sets. It’s the ultimate “beat the data with a stick” program. It can yield garbage… (generally if you feed it garbage) but it’s pretty good at coming up with something. So, I turned it loose. It turns out, that if you have a delay of 1405 days, it can roughly predict the temperature in Greenland from the running detrended integral of the Volcanic activity with a correlation coefficient of 0.7177. (Actually pretty good considering where we started out from) I calculated a sigma for the function based on what the formula predicted and what the actual data was.

That… was distraction 3.

What’s it all mean? Beats me. Greenland is just one point on the globe. There seems to be a 1405 and 1422 day delay relationship in the data, or about 3.8 years. Formulize also ground on a 4.13 and 4.44 year offset for a while. It was quite fun watching it dance back and forth with the delay. Make of it what you will.

And now the all important caveat: I am not a Geologist or trained in any of the fields that have been touched on in this post. My specialty is electronics and cross correlating threats… if you must know. (such as the 230 knot Shvall torpedo tested by Iran having been designed for 533mm torpedo tubes postulated as a design criteria… and the the Kilo class sub launched from Bandar Abass last week or so, having six 533 mm tubes. And that’s all from published data in various sources on the web.) But.. I don’t do that anymore. Volcanoes will have to do.

What to take away from this post, something that can be used by my fellow volcanophiles, is the first plot. You can find a hole in the ground in Google Earth and do a ballpark estimate of how much material may have come out of it when it initially formed. Remember that it may not have all happened at once.

Several thousand years of activity can produce the same effect.

Enjoy!

GEOLURKING

Sulfur dioxide initiates global climate change in four ways – Ward (2009)
http://tetontectonics.org/Climate/SO2InitiatesClimateChange.pdf
And the table:
http://www.tetontectonics.org/Climate/Ward2009TableS1.pdf

Hayakawa Paleovolcanology Laboratory
http://www.edu.gunma-u.ac.jp/~hayakawa/English.html

Recurrence rates of large explosive volcanic eruptions – Deligne, Coles, and Sparks (2010)
http://www.globalvolcanomodel.org/documents/Deligne%20et%20al%20(2010).pdf
Data Set
ftp://ftp.agu.org/apend/jb/2009jb006554/2009jb006554-ds01.pdf