Image by Cenapred. Popocatepetl after it blew through the dome extrusion.
Mexicos Popocatepetl started it’s long awaited new eruptive phase after a dome extrusion. As I wrote a week ago the eruption was expected to be small, and so was the case. Everything points to a VEI-1 or VEI-2 eruption. The only real danger currently is lahars, but since the glacier ontop of the volcano has diminished quite a lot during the last decade any lahar will be smaller then previous lahars. Popocatepetl will most likely continue to erupt in phases, alternating between dome extrusions and ashy explosions like today.
Webcams for Popocatepetl
http://www.cenapred.unam.mx/popo/ImgPopoTlamacas.html
http://www.cenapred.unam.mx/popo/UltimaImagenVolcanI.html
Mount Turrialba could not stay out of the fray and had an increase in activity today with vigorous steaming, an episode the finnished with an ash/steam-explosion.
See image 1 and 2.
Image by Ovsicori. Turrialba before the explosion.
- Image by Ovsicori. Turrialba after the explosion.
Webcam for Turrialba:
http://www.ovsicori.una.ac.cr/vulcanologia/liveturrialba/camara.jpg
Photograph by HMS Endurance (courtesy of John Smellie, British Antarctic Survey).
Zavodovski is one of those volcanic Islands you quite often never have heard about unless you are an avid sailing fanatic. It last erupted at 1908 according to Lloyd’s of London. Nothing beats them on things on Islands. The volcano on the Island is named Mount Curry, to my amazement I found that it had another name too, Mount Asphyxia. No doubt to the large output of SO2 from the volcano, also the large amount of bird poop on the Island would not help… Be that as it may, according to NASA it is now vigorously erupting. I will get back to this splendidly interesting volcano as soon as I can.
CARL
VolcanoCafé 
Small bit of steam seen on Mt St Helens earlier: http://oi49.tinypic.com/a59vd2.jpg
Original link: http://www.fs.fed.us/gpnf/volcanocams/msh/hdimages/volcanocamhd.jpg (cloud there at the moment)
& there appear to be hot fumeroles on Etna tonight: http://www.radiostudio7.it/webcam.asp?web=1&id=1
While I’m still fuming over the arrogance of some “code writers,” some light reading
http://etd.ohiolink.edu/send-pdf.cgi/Kelley%20Daniel%20F.pdf?osu1244046067&dl=y
It’s a link to a thesis a guy wrote towards his Doctorate in Philosophy (eh?) titled “Toward an Integrated Model of the Crust in the Icelandic Rift Zones”
I mention it since he includes a few magma chamber depths for the Icelandic systems.
Yepp, that is where the Ph comes for. Philosophic Doctor, it is to kind of make a difference from those pesky MDs…
I perhaps should clearify this.
MD = Medical Doctor
Ph.D. = Philosphiae Doctorem, or Doctor of Philosophy in (insert subject)
TD = Technologiae Doctorem (engineers)
In order of pompous ass that would be Ph.D., TD, and then somewhere below are MDs since they do not have to do a dissertation and the other stuff…
The Philosophic part comes from philosophy being seen as the mother of all sciences, albeit not a science in and of itself.
Philosophy is much more fun than science:
The Universe is a machine the purpose of which is to amuse and baffle its inhabitants.
Man created God in his own image.
Cogito, ergo sum.
In England medical doctors are MB ChB. I’ve no idea what that stands for! Once medical doctors become consultants they get called ‘Mister’ again instead of ‘Doctor’ – I’ve no idea why that happens either! 🙂
MB = Medical Bachalauraete. Master of Medicine.
ChB = Chirurgical Baccalaureate or, with the vulgarisation of languages prevalent today, Bachelor of Surgery.
Ph.D.. Although the study of logic, ontology and epistemology seems no longer a requirement.
Nah, you are all wrong. 😀 😀
PhD = Piled Higer and Deeper, see this:
http://www.phdcomics.com/comics.php
Warning: this is addictive, so read the archives at your own risk and only if you have a free afternoon.
Presumably, that photo by HMS Endurance is from the ships helo.
If not, that is one tiny little island given the viewing angle…
Wednesday
02.05.2012 19:58:10 64.702 -17.412 2.5 km 1.7 90.01 8.8 km NE of Bárðarbunga
Failing at finding a good estimate of temperature data for the Vedivotn – Eldga magmas… I opted to try and get / manufacture and estimate of my own. That’s one reason I got so @#$ pissed off at the lazy codewriters from that site I was ranting about.
I have quite a ways to go, but here is a boiled down version of what I am doing.
First, the crystals in magma form at different temperatures. As they form, the trade and or strip elements from the melt at various rates, depending on the temperature. If you can get a handle on the ratios, you can eyeball/estimate the temperature of the magma. A real petrologist with the right gear can nail the temperature within a few degrees… but I’m not a petrologist.
So, focusing on Albite and Anorthite, the end members of the plagioclase series, I can (well, we as in all of ‘yall and me) get a estimate of the relative temperature of the magma.
Refering to http://csmres.jmu.edu/geollab/fichter/IgnRx/SolidSol.html
You will note that Albite forms mostly at the low end of the temperatures, and Anorthite forms at the higher end.
Albite is NaAlSi3O8, Anorthite is CaAl2Si2O. In each molecule, there is one Ca or one Na.
Using multiple sources, such as Tephrabase and http://www.therafoundation.org/articles/volcanology/ashlayersofthetheravolcanicseriesstratigraphypetrologyandgeochemistry for Thera, I plotted the ratios of Ca to Na across the different SiO2 mass percentages (mainly because I needed an X axis) to see how various eruptions stack up.
From other literature, we know that Laki’s magma was about 1160°C.
Remember, I don’t have the temps of the other magmas, but this should be an accurate assessment of the relative temperatures. Cooler magma is towards the bottom of the graph, hotter is higher on the graph. (More Ca points towards higher temperatures)
The plot.
REQUEST
Any link to a paper or reference that gives the geochemical makeup of the THa through THi tephra or magma. (Thjorsa – part of Vedivotn), Eldga, Laki
Any link to a paper that gives an estimate (a real estimate, not a media hype peice) of the temperatures of that magma/tephra.
Any link to a paper that gives an estimate of the dike size for those same systems. I used a ballpark estimate based on 10% of the average graben width. (no particular reason, 10% seemed sane)
Thanks in Advance.
Interesting plot. Hope you can get the information you need.
This might help for Laki: http://petrology.oxfordjournals.org/content/48/7/1265.full.pdf+html
Actually that helps a lot. It’s a much more detailed look at the geochemistry of the Laki material.
Thanks!
This seems very detailed on Eldgjá…. http://www.sciencedirect.com/science/article/pii/S0377027300002778
Paywalled – Elsevier Tax.
This may be interesting but it is stuck behind a pay-wall. http://www.sciencedirect.com/science/article/pii/S0009254108002623
* Thjorsa lava
Any interest in intrusives?
sent mail to Carl
And you also see why the lavas of Laki and Veidivötn are so interesting. The lower the SIO count, the higher the count of the goody parts.
would this be of any help, although I’m sure Carl probably has it already?
http://onlinelibrary.wiley.com/doi/10.1002/jqs.1129/abstract
Late Quaternary terrestrial tephrochronology of Iceland—frequency of explosive eruptions, type and volume of tephra deposits†
Gudrún Larsen*, Jón Eiríksson
http://www.eldgos.is/storgos-eftir-landnam/katla-eldgja-934
* will try finding ref in Icelandic texts *
http://volcano.oregonstate.edu/vwdocs/volc_images/europe_west_asia/eldgja.html
http://scholar.google.is/scholar?q=~935+AD+Eldgja+eruption,+Iceland:+Journal+of+Volcanology+and+Geothermal+Research.&hl=en&as_sdt=0&as_vis=1&oi=scholart&sa=X&ei=lrehT_WQB8zZ4QSf5_SjCQ&ved=0CBgQgQMwAA
Nice Aqua/MODIS pic of Zavodovski from five days ago.
Some hot Karman vortex action going on there, including the clouds off the other islands.
(it is awfully childish to laugh at people’s names, but I couldn’t help smirking at the photo of Mt Curry being credited to a Mr Smellie)
🙂
Given that the other name for the mountain is Asphyxia…
Navy humour perversion inspired by Red Dwarf? Y’know, the tv-series where the commander loves his curries and farts evily?
And now I got nostalgic…
As I did being the Child of the 70s that I am when a certain Someone christened a hut the “Burfell Dalek” – ekksssterrrminate!
Yeah, being kids of the seventies give a sort of nostalgic cultural background 🙂
Seems to be a bit of steam coming off Etna in the thermal webcams: http://www.ct.ingv.it/index.php?option=com_wrapper&view=wrapper&Itemid=202&lang=it
Also visible on cam2 (illuminated by the Moon) http://www.guide-etna.com/webcam/
I did find an SvV sample that is from Veidivotn.
Based on my earlier data, it seems to be pretty close to Laki.
This may seem “obvious” but it is evidence that the temperature of the source material is pretty close.
Interesting. Iceland is a large igneous province: are we looking at something akin to flood basalt at Laki and Veidivotn?
But it’s well past my bedtime so BBGN & shleep well.
They are both flood basalt phenomena.
If I remember correctly, the source of the TH(x) series of tephra/magma (Veidivotn) put down about 35 km³ of magma in one or two flows. But that was before historic times. Eldga – 18 km³, Laki – 15 km³.
Flood basalts are a lot more common that you might think. The Columbia Flood basalts have their origin about the same time that a significant portion of the Farallon went under, and at about the same time that the Yellowstone hotspot started it’s trek. The Deccan Traps are another, with flows totaling more than 2km thick.
I’m not certain, but I think that some phases of the African Rift Valley have done flood basalts… but that doesn’t tend to stack up. (it’s a spreading center).
Once upon a time, the Iceland Hotspot was at the same location (spatial as well as temporal) as the formation of the Siberian Traps. http://t0.gstatic.com/images?q=tbn:ANd9GcSWu2elQPWEGhUVEDkOv-ksi6r_Yyhp1h9_ZWIYB6JZ4myB7_oKWQ
Are we going to find the source of Siberian traps?
Thanks, Lurk!
Yepp, It is called Icelandic Hot Spot nowadays…
Err…. “GAH?”
Here is a reasonably good guess. Published data states Laki had a temperature of about 1160°C
…At Laki’s eruption temperature of 1160 °C, there is about 25–45% cumulate removed and similar amounts of assimilant added using the above AFC model…”
“Time constraints on the origin of large volume basalts derived from O-isotope and trace element mineral zoning and U-series disequilibria in the Laki and Grímsvötn volcanic system” Bindeman et al.
Looking about the web for ways of doing the temperature estimate (aside from the one I came up with earlier) I found this.
http://www.mantleplumes.org/HawaiiFocusGroup/Sisson_abs.html
Essentially, using the weight percent of MgO to estimate the temperature. Using more advanced methods, the author adjusted the data down to 30 kbar… I didn’t even try to go that far, I just wanted a reasonably accurate guess at the magma temperatures at eruption.
So, taking that idea, and finding the temps of the two samples that he used, and then finding a temp for typical MORB basalt, I went in search of the MgO content of typical MORB basalt. I found a set of data that adjusted all of its calculations against “8%”.
Throwing that in, and adjusting for the published Laki temps, I have this guestimate of the Veidivotn magma temps.
For Carl… I recommend that you squirrel this one away for when you write the post after I get this Veidivotn thing figured out.
G’night.
Bonus plot. Since I had it in the spreadsheet, here is the same data over a crapload of Tephra samples. Most of them from Tephrabase, some from Thera at
http://www.therafoundation.org/articles/volcanology/ashlayersofthetheravolcanicseriesstratigraphypetrologyandgeochemistry
Notice that the higher the SiO2, the cooler the source magma is. That fits with the highly evolved magma (more Rhyolitic or silica rich) being mobilized older material.
Yay… typo.
Attn Spelling Nazi’s – piss off.
Mg count is between 8% and 45% weight.
Hint, the temperature is very low, it is hotter. The Mg content is way higher for all of the Bardarbunga and Laki lavas.
Laki 3 is for example almost pure forsterite… Magnesium Olivine. And that took some temperature to melt…
Hotter for the Veidivötn and Laki that is…
Laki temperatures are also to be found in this text: Guilbaud, e.a. http://seismo.berkeley.edu/~manga/LIPS/guilbaud07.pdf eg. p. 21 and p.25. The text is from 2007, maybe that there are more actual data still.
The highest temperatures mentioned there – as far as I saw – are 1180°C. (p.25) 🙂
Reposted after adding to the wrong blog.
After not sleeping much and thinking about this all night could I ask a question without being pulled to pieces.
Could the possibility of the erruption in Mexico affect the Rivera Maya where we are due to go in 10 days . I know its miles away but if it errupts fully what about an ash cloud etc.
I have to laugh to myself (well its better than crying) dont think my situation can get any worse .
Have done some investigations and there is a chance that flights to Cancun could be cancelled if there is a full blown erruption with an ash cloud forming so again my holiday seems to be in the lap of the gods.
Nothing points towards the eruption becoming bigger right now. The tremor is rather steady, no increase in quake rate, I would actually say it is diminishing now. What I will keep my eye open for is the next dome extrusion.
Why will I keep my eyes on that particular thing? Well, when the dome is extruded the pressure builds up, and if the dome is the same size as the last one that blew out yesterday, then you will be fine.
Hey, you are on the perfect place to get help with this, and with this I promise everyone will pitch in for you 🙂
I too posted an answer in the previous pages.. here it is again…….
Diana Barnes says:
May 3, 2012 at 07:51
Hey Judith.. I looked it up and the distance between Popo and the Riviera Maya is about 800 miles. If you are flying to an Airport on the Mayan peninsula there will probably be no problem.. To put it in perspective, Eyaf eruption was really a “normal” Volcanic eruption that affected world Air travel, This was due to an unusual set of weather conditions Airlines have learned much fom that experience.
I could be wrong but I don’t think Popo’s eruption will make any difference to your travel and stay.
Here is an interesting link about Mexican Volcanoes and other stuff…..
http://geo-mexico.com/?tag=volcanoes
Judith try not to be so anxious. You will only make yourself miserable. Live for each day. Each day brings a new experience. Sometimes not good but Hey! You are going to an exciting place. I always wanted to see the Mayan temples….You are lucky…..I can no longer fly to such places… hence I Travel round the world on my PC….It’s wonderful
I Remember what my Grandmother always told me when I fell down and hurt myself. ” Does it Hurt?”……”Yes!” I would cry
“Then you are not dead”. She would say, smiling.
It used to really irritate me and took a while for me to understand the very positive thinking behind this simple statement… but she was so right 😀
Reply
Now judith, you pack your stuff and get going! Otherwise you’ll regret it the rest of your life, you’re in for a treat. Mexico is a great country of good people!
Life can be dreary and boring, you need to recharge once in a while. Let me remind you of the “ash disaster” in Europe. Everybody survived, not a single casualty, all the stranded passengers got home, each with their own survival story. But for a brief while we were all in the same boat, we had a lot to talk about, even to complete strangers. And life was good!!
Have a safe journey, and give us a report when you return. Meanwhile Volcanocafe will handle Popo in your absence!
Judith, it was only the thing with all the quake reports. It is just that there are so many quakes happening that it kind of becomes very many. Just post those you find really interesting (with link) and you will be fine. Promise 🙂
Regarding your trip.
It would take something 2 orders of magnitude larger (much much bigger) than what we are seeing now, and also that the wind was in the perfect direction (perfectly wrong direction depending on how you see it) for your airport to get closed down.
I would say that it currently would be less than 1 percent chance of the airport getting closed.
Judith, I will keep an eye out for you and try to do a prediction on a daily basis for how the ash will be when you go. Just keep an eye out. For now it looks really good for you.
The biggest tisk from Popocateptl historically is lahars. Current volcanic ash advisory – seems to be a small ash cloud: http://www.ssd.noaa.gov/VAAC/ARCH12/POPO/2012E030641.html
But it is 10 days until your holiday so time for Popo to complete the eruption before you set off. I think you should plan to enjoy your holiday – you deserve a break 😀
@ Lurking the Great
Assume you have this in your ‘armoury’! any relevance?
http://www.geokem.com/OIB-volcanic-iceland.html
Geochemistry of Igneous Rocks
“Atlantic Ocean Volcanism,
OIBs, Tholeiites and Basanites
(Ocean Island Basalts)
(1) Iceland “
Don’t know if this is relevant – wouldn’t download for me!
Click to access Jagan2010.pdf
Thank you all for your comments I really mean this and Diana your Grandmother was so correct and she would have probably had a few things to say to me at the moment !!! We plan to go to Tulum to see the ruins will take lots of photos. So positive thinking for me and looking forward to my adventure in Mexico.
Does anyone want me to bring any rocks etc back for them Diana I still have roots in Yorkshire and could post them to you.
Have a wonderful time – Tulum is a fantastic place. No kidding, I am currently drinking coffee out of a mug that my wife had made for me years ago showing (a very youthful) me at Tulum with white sand, azure sea and great ruins.
And Búrfell had a twitch during the night…
http://hraun.vedur.is/ja/hekla/thensla_burfell.html
Anyone else noticed the high amount of M4+ near the Iraq-Iran border recently? I’m kinda expecting a big one now.
Ah, let us hope not.
That would do a lot of nasty stuff with the oil-prices. Because every percent of the oil-infrastruce in that area that gets damaged would hammer us with an equal percentage or more of increase in crude oil.
Oh, forgot… Judging from the spot I would not be entirely surprised if the quakes originate from faltering old oil-fields.
Isn’t the border also the zone of a convergent plate boundary? Prone to pretty destructive earthquakes. Yeah it wouldn’t be all to good for oil, but let us not forget the people in this area.
If I remember correctly the convergence boundary is inside Iran. Only spot that I know of in Irak that is on the convergence boundary is deep into Kurdistan.
Not too far from a subduction zone: http://neic.usgs.gov/neis/bulletin/neic_c0009hz9_l.html
And recent activity: http://neic.usgs.gov/neis/bulletin/neic_c0009hz9_h.html
Similarly there has been a swarm of earthquakes near the west coast of Turkey today – perhaps 20 above 2.0mag and several above 4.0 including a 5.o
Have not seen many earthquakes in this region hope this is an interesting one.
mb 5.2 Region GANSU-NEI MONGOL BDR REG, CHINA Date time 2012-05-03 10:19:39.0 UTC
Location 40.55 N ; 98.74 E Depth 10 km
http://www.emsc-csem.org/#2w
Is this just pure coincidence it happened ten minutes after the large 5.5 Iran quake.
Hi Judith! This is the first quake this year in the area, which is why you haven’t seen one before. However, the historic seismicity map shows that there is quite a lot of activity in the area.
http://neic.usgs.gov/neis/bulletin/neic_c0009hzf_h.html
I hope you enjoy your holiday – don’t forget we only know about volcanoes and so on now because of the internet. 800 miles is a long, long way. If anything untoward ever happens to you, treat it as an adventure rather than a mishap. By the way – I’m green with envy about your holiday, I’d love to be able to afford to go to Mexico! 🙂
Thanks Talla .
Normaly the quakes in that area is rather big. It is on the upper boundary of the chinese compression zone.
And yes, you are spot on that it is nothing more than a coincidence with the Iran quake.
Carl, here is another one for the “silly season”. Underwater eruption suspected near Iwoto, Japan.
http://www.yomiuri.co.jp/dy/national/T120430003314.htm
That back arc of Marianer trench is so fascinating, thousands of volcanoes ranging from bay of Tokya past Iwo Jima and then onwards.
I didn’t realize until I did some further reading, that Iwoto is actually Iwo Jima.
Yepp, Iwo Jima also known as stinky island.
Iwo Jima is actually one to keep a very close eye on. It has experienced (and still is) dramatic uplift of over 50 meters in the past 700 years centered in the caldera… Draw your own conclusions.
I even found a paper statin the uplift since 1600 is 150 meters.
Interesting:
http://rsta.royalsocietypublishing.org/content/364/1845/2055/T1.expansion.html
Thanks Pieter, very interesting! Is the uplift due to volcanic inflation alone? I doubt it given its geographic location on the Marianas arc on top of the subduction zone. Also, at the rate of inflation give and if you figure in the height of Iwo Jima, 160 m, it would have been submarine until about 1500AD. Another inference from the list you quote is that even if the overall uplift 1600 to present is 120 meters, the rate between 1911-78 is half that of the overall, i.e. it has slowed down. Now, if we asssume uplift due to tectonic forces to be more-or-less constant, uplift due to volcanism cannot be less than 80 meters which is still pretty impressive.
John Seach – http://www.volcanolive.com/iwo.html – says “Uplifting rate of Iwo-jima island is very high. During 1911 to 1952 uplift was 11 cm per year. Uplift was 33 cm/ year between 1952 and 1968.” He goes on to list several eruptions of which the last in 2001 produced a pyroclastic cone (i.e. wasn’t phreatic) which means the information on royalsocietypublishing you quote isn’t quite accurate.
GVP on Iwo-Jima – http://www.volcano.si.edu/world/volcano.cfm?vnum=0804-12= – gives the nugget that the beach Captain Cook landed at in 1779 is now 40 m above sea level (i.e. a rate of inflation of 17.4 cm per year).
I’d not expect to much of the tectonic uplift as Iwo Jima is out of the main compression belt along the subduction zone. Also, the recorded uplift is clearly from the middle of the caldera, which implies a magmatic cause rather than a tectonic one. Nevertheless tectonic forces should be taken in consideration.
Yes the inflation rate would imply that Iwo Jima was submarine not too long ago, but don’t forget that volcanic islands like these change shape often due to active volcanism and strong water/wind erosion. It could very well be that Iwo Jima was submarine before 1500AD. The first documented reports date from 1779, when Cook landed. This certainly gives room for the idea that the island was very young at that time, and was submarine just several ages before.
Why do you figure a phreatic eruption can’t produce a pyroclastic cone? A ‘Phreatic eruption’ means the interaction between magma and water, which is very well capable of producing ash to build a cone.
Aren’t you confusing phreatic with phreato-magmatic here? A phreatic eruption is basically water heated by but not in direct contact with magma flashing into steam which may carry old material with it. Such material can’t build a cone.
Henrik, Eyja was a phreatic eruption…
Surtsey was a phreatic one up untill the end when it had a subsidiary eruption that was basalt lava flood.
Phreatic eruptions normally produce a lot of tephra and pumice…
Sorry, both Eyja and Surtsey are examples of phreato-magmatic eruptions where magma came in direct contact with water. It is sloppy usage of poorly defined terminology that causes misunderstandings and misinterpretations like these.
The site Pieter quotes says there have been NO ERUPTIONS at Iwo Jima, yet there are about a dozen events listed at the GVP as phreatic and John Seach has one, the last one in 2001 as forming a pyroclastic cone. You can’t have it both ways. Either the site quoted by Pieter is horribly unscientific or wrong OR, provided you accept that phreatic explosions do not involve magma directly, they can all be correct. Your choice…
As I have understood it the phreatic part of the eruption is before it surfaces (Surtsey part one), phreato-magmatic when it is surfacing (part two), and then it turned magmatic (Surtsey part three).
But, I agree, it is poorly defined.
But we have to give the volcano-guys a bit of slack, it is a rather new science after all.
Interestingly, the Lowenstern paper Pieter refers to below lists some stats on Iwo Jima:
120m of uplift over 400 years at a rate of 30cm per year. Yikes.
oh, crap, scratch that. It’s the same paper he referred to above.
Dr Behncke’s explanation over at Eruptions (on Erik’s Yellowstone topic):
“Similar events, both offshore but sometimes also from vents on the island occur every few years. These are tiny phreatic eruptions – caused by water coming into contact with hot rock at shallow depth.”
Sounds like Boris uses about the same definition as I did for phreatic.
Carl ffs, don’t be obtuse! He says hot rock and not magma. Give in…
😈
And a hot enough rock would be..? Olivine 🙂 Forsterite has a wild melting point.
I take it as he mean hot rock, either as lava or as insanely hot unmelted rock.
Forsterite at 1400C is not a molten lava for instance.
So, let us be definitiously
Oh Carl. Not only are you unable to differentiate between rock and magma, now you confuse magma with lava as well. Oh dear, oh dear…
PS. I’m certain that if Dr Behncke had meant magma, he would have said so. If he meant lava, he would have said so. If he meant both, he would have said molten rock. Did he? No. He said “Hot rock (at shallow depth).” 😛
😉
Why not ask Messieur Boris himself?
Magma, before leaving the eruptive orifice.
Lava, after leaving the eruptive orifice.
Ha, not only do I enjoy two brilliant minds having a raving argument about semantics but I am stupid enough to join the fray, provided it is understood in the spirit of camaraderie and great respect for both of you:
I am siding with Hendrik on this one. Phreatic in my understanding is a geothermal process when ground water flashes to steam creating a blast pit usually. Happens frequently in Rotorua for instance and catches people unawares. Great way to lose your vege garden or cook your carrots and simultaneously deliver them to your neighbors down the block.
Phreatomagmatic, as I understand it, is an eruptive process of flowing magma coming into contact with water, which when in the right proportions can lead to lovey rooster tails like at Hunga Tonga. (what a pity Surtsey erupted before Hunga Tonga, otherwise we could say pretty hungan roosters, oh well).
I am happy that we are not talking about well Hungan Roosters…
PS, while looking picture of Hungan splendour, I came across this old posts of Erik with a nice definition of the two:
http://www.google.de/imgres?imgurl=http://www.virginmedia.com/images/tonga-volcano2-430×300.jpg&imgrefurl=http://www.wired.com/wiredscience/tag/hunga-tonga-hunga-haapai/&h=300&w=430&sz=26&tbnid=T9Y3bdfpQOfutM:&tbnh=90&tbnw=129&prev=/search%3Fq%3Dhunga%2Btonga%26tbm%3Disch%26tbo%3Du&zoom=1&q=hunga+tonga&docid=CBu2kST57d12rM&sa=X&ei=hNSiT4rVFIjKtAbqjMG1Bw&ved=0CD4Q9QEwAw&dur=535
crikey, “looking for pictures of” (why does my typing go to pot on this site)
I’m perfectly happy to accept Erik’s definition. Thank you Bruce for helping settle this argument. My £5 please Carl:
Nice very deep quake-swarm happening up in Tjörnes.
This is on the western rift of the micro-plate associated with the Theistareykjarbunga volcano.
Notice the extreme depth of the earthquakes, that s quite interesting. Probably a deep slip lock giving way. These are not volcanic earthquakes per se, but are releasing the micro-plate which might in the future increase the magmatic tension at Theistareykjarbunga.
http://en.vedur.is/earthquakes-and-volcanism/earthquakes/tjornes-small/#view=map
With many quakes at 18 – 23 km depth, it’s basically at the intersection between crust and mantle (or Moho) which at the location of those quakes is 20 km thick http://www.tobias-weisenberger.de/6Iceland/Introduction/Abb2.4.jpg
Yepp, that is why I found these to be interesting, they are on the extreme end of what should be possible there.
And we also have that ultra-weird twisting motion of the micro-plate. Due to the twisting motion it is really tearing and slamming into north american plate at the same time. Must be putting a lot of back strain on Theistareykjarbunga.
If the Husavik and the Grimsey quakes are real we can actually see almost the shape of the micro-plate now.
This is how propagating earthquakes look like as they travell around interconnecting fault-lines Judith. They really do not go far, but are interesting the few times they occur.
Judith, I’ve been popping in to keep up with the blog, but haven’t had much posting time. I wish you well with your health. Remember – a positive attitude is good medicine, too. I am glad you have decided to go on your holiday. What a wonderful place to be going. Enjoy every minute and take lots of pictures to share with your envious bloggers. 🙂
Thanks Bobbi.
Hey Judith , managed to get on for a bit, but I am having a hard time keeping up with what is going on.Sounds like hubbie is on the mend, and I hope you are doing ok. I think it is great that you are going on your vacation, have a wonderful time, relax and enjoy.
Another Volcano waking up ?
EXPLOSION IN THE LOKON VOLCANO IN INDONESIA.And another that notes these days, the Lokón, located in Tomohon – unos10km South of Manado (incidentally that this volcano is on the edge of the large 20x30km Tondano caldera) has had an explosion at 11: 55 a.m. local time, which has been more of what came to be his normal, with a column of ash activity of more than 2.5 in height. The airport in the North of Sulawesi has closed. The evacuation order for anyone who lives is given to less than 2.5 of the volcano.
http://www.thejakartapost.com/news/2012/05/01/Mt-lokon-erupts-again.html
This is the story I got when I followed the link:
“Mt Lokon erupts again
The Jakarta Post, Jakarta | Tue, 05/01/2012 1:05 PM
Mount Lokon volcano in North Sulawesi erupted again at 11:55 a.m. local time on Tuesday. The latest eruption was larger in magnitude compared to the eruption last Wednesday but local residents were more prepared. The eruption was preceded by a number of mild earthquakes over a span of two minutes. National Disaster Mitigation Agency (BNPB) spokesman Sutopo Purwo Nugroho said smoke plumes reached 2,500 meters in height when Mount Lokon erupted. According to geologists with the Volcanology and Geological Disaster Mitigation Center (PVMBG), it is not time for residents to evacuate yet, but evacuation sites are being prepared just in case. The BNPB has deployed a team to keep the situation in Mount Lokon under control. The agency has also prepared transport, Rp 400 million (US$43,600) in cash and other equipment. Other emergency teams are on stand-by in Malang’s Abdul Rahman Saleh Airport with Hercules C-130 aircraft ready for evacuation. “Everything is ready,” Sutopo said. (nat/swd)”
Can’t see a reference to an explosion there. Do you have a more up to date link?
But if you check, you’ll find that Mt Lokon has been on orange alert for some time now. http://www.vsi.esdm.go.id/
These are the Spanish comments I translated from which were posted on Avcan .
Como estaba ayer el volcán Popocatépetl y unas imagenes espectaculares de la actividad volcánica, que a pesar de ser pequeñas explosiones, son espectaculares. Ayer este volcán lanzo cenizas a mas de 1 km de altura sobre el cono, y de como viven sus pobladores, para empezar con la caida de ceniza…
Er…..that’s Popo not Mt Lukon.
I am a dingbat with a very red face !!
EXPLOSION EN EL VOLCAN LOKON EN INDONESIA.
Y otro que se hace notar estos dias, el Lokón, situado en Tomohon — a unos10km al sur de Manado (por cierto que este volcán está en el borde de la gran caldera de Tondano de 20x30km) ha tenido una explosión a las 11:55 a.m hora local, que ha sido mas grande de lo que venia siendo su actividad normal, con una columna de cenizas de mas de 2.5km de altura. El aeropuerto del norte de Sulawesi ha cerrado. Se da la orden de evacuación de todo aquel que viva a menos de 2.5km del volcán.
http://www.thejakartaglobe.com/news/north-sulawesi-airport-should-be-closed-after-volcano-eruption-expert-says/515284
Hey Judith, I did one worse. I posted a cartoon I was watching instead of an eruption video. You at least where on topic, just the wrong volcano. 🙂
I wrote a long comment about the ash coming out of the volcano, and posted a video of Family Guy… 😳
Thanks, Judith.
I’m glad people are aware of the dangers of the poisonous ashes and evacuation roads are being fixed.
Very interesting paper on large caldera systems and ‘supereruptions’.
http://rsta.royalsocietypublishing.org/content/364/1845/2055.full
But while I was checking out Mt Lokon above (seems to have quietened down for now, at least), I found another erupting volcano: Batu Tara
http://www.volcano.si.edu/reports/usgs/
http://www.bom.gov.au/products/IDD41290.shtml
This is starting to really be silly season…
5 eruptions and counting…
Another link for up to date errupting/active Volcanoes.
http://www.volcanodiscovery.com/erupting_volcanoes.html
Beautiful view of Mt. Hekla today. Hope it does not make it to the list before BBQ is over..
http://eldgos.mila.is/hekla/
Beautiful! 🙂
I just hope that some kindhearted icelander would wipe the sticky fingerprints off the beautiful Hekla webcam picture!!!
@Mike. Easier said than done. Its no fingerprints (camera is high up a antenna mast and no one can reach to it) but more likely is volcanic dust from our most recent eruption and therefore “very on-topc” in any tread – your choise!! When the “dead zone” goes off, there will be no web-cameras, all destroyed by lava flow, tepra fall, countless Lightnings or blizzard like sand-storms.. 😉 *teasing*
Latest report from http://www.volcanodiscovery.com/erupting.volcanoes
Summary of world-wide volcanic activity 25 April -1 May 2012
Thursday May 03, 2012 11:19 AM | Age: 2 min
BY: T
The new Smithsonian / USGS Weekly Volcanic Activity Report was published today and is summarized as follows:
— new activity —
Batu Tara (Sunda Islands, Indonesia): occasional ash eruptions, plumes up to 2.4 km altitude
Cleveland (Aleutians, Alaska): new small lava dome 25 m across detected
Iwo-jima (Ioto) (Volcano Islands, Japan): small eruption on 2 May, lake water discoloration
Lokon (North Sulawesi, Indonesia): occasional ash eruptions, plumes reaching 3.7 km altitude
Popocatépetl (Mexico): gas-and-steam emissions, occasional explosions ejecting lava bombs up to 1 km, crater glow
— ongoing activity —
Bulusan (Philippines): decline in activity since last phreatic eruption in May 2011, alert lowered to normal
Etna (Sicily, Italy): New SEC paroxysm nr 25 on 24 April
Karmysky (Kamchatka): occasional small ash eruptions, thermal anomaly at summit crater
Kilauea (Hawai’i): active lava lake in Halema’uma’u crater, active lava flows advancing on coastal plain to within about 900 m from coast
Nevado del Ruiz (Colombia): strong degassing, possible phreatic explosions, eruption warning
Sakurajima (Japan): ongoing occasional vulcanian eruptions, ash reaching 2.7 km altitude
Santiaguito (Guatemala): lahar on 25 April, viscous lava flows and occasional explosions
Shiveluch (Kamchatka): continuing strong ash explosions up to 10 km altitude, viscous lava flow in 2010 crater
Soufriere Hills (Montserrat): low level of activity, recent rockfall and pyroclastic deposits observed
Tungurahua (Ecuador): intermittent explosions, ash venting, ash fall
—
Links / Sources:
Smithsonian / USGS Weekly Volcanic Activity Report
Shiveluch is just steaming gently now, girding its loins for another ash-fart. No big explosions for a few days now.
http://www.kscnet.ru/ivs/video/Sheveluch.html
Kliuchevskoy is quiet at the moment, but it is looking utterly magnificent this morning
http://www.kscnet.ru/ivs/video/Klyu.html
Oh my! Fabulous! 🙂
That is one beautiful volcano! Thanks for that link–is weather usually that clear?
What is Vatnsfell doing? http://hraun.vedur.is/ja/oroi/vat.gif
Uhm…
I hope this is local storm.
But it sure does not look like it.
My hopefull guess is a Jökulhlaup. (Fingers crossed)
Sorry—I missed it—what is a jokulhlaup? And what is the other option?
Glacial flood (but they do not come in this location)
Thanks- learn something new everyday!
The other option would give us quakes soon…
where is that station? Any volcano associated? All the stations are with strange behaviour…
Nah, all stations are not showing strange behaviour. A couple are a bit “odd”. But this is strange.
This is “thee” tremor station.
Hell opening up™, Ice-cream sold at convenient places, and so on.
But, I still say a storm or perhaps a Jökulhlaup from Vatnajökull taking an odd direction.
Envelope of the increase is 1,5 hours.
If it was the other option I think we should see activity at GRF, DYN and JOK.
But no action in low frequencies. So, hoping for a local storm. But I have never seen one.
The Vatnsfell SIL station is just off the southern shore of lake Þórisvatn and if Veidivötn or Eldgja decided to open up it is, as Carl points out, the SIL station to watch.
It started around this one, but it is a wee bit weakish…
Thursday 03.05.2012 16:49:26 64.531 -17.641 1.1 km 1.3 32.03 9.4 km ENE of Hamarinn
Thankfully it stoped now…
It seems like it could have been outlet from a hydro-power plant (info from Islander).
@Carl. 18:49
But why does it show at Skrokkalda, too?
What could be the same event also shows up at Askja, Krokottuvotn but not at Grimsfjall. At both Austmansbunga and Fagurholmsmyri the spike is too early albeit the instant spike at the former may coincide with the onset of the episode. Hmm…?
I think the rest is mostly wind, it does not show up as anything special at most of them.
FAG is the same, also JOK shows it, and a tiny bit shows at GRF.
There was some action at Grímsfjall in low frequencies, I think. http://hraun.vedur.is/ja/oroi/grf.gif – as well as some confirmed quakes at Bárdarbunga and Gjálp. http://www.vedur.is/skjalftar-og-eldgos/jardskjalftar/vatnajokull/ So the Jökulhlaup option could still be open.
Ok. But there are water meters up near Hamarinn – anybody checked on them? I do not have links anymore, they were on other browser that had a CBD (Crash, burn and die)
Checked. Seems spring is coming. Much water in river at Sveinstindur, but no flood (yet) and day/night spikes are ruling – All seems normal. http://www.vedur.is/#vatnafar
It seams we still see some unrest here…
a swarm starting in Tjörnes fracture zone … http://en.vedur.is/earthquakes-and-volcanism/earthquakes/tjornes-large/
On the Avcan Facebook page there is a photo a 3d echo of the volcanic cone.
,,Good afternoon, in this link you can see the images captured by the multi-beam echo of the Atlantic Explorer QSTAR SLU B/O during the campaign Guayota 3escogidas by Antonio González Ramos as the most interesting of the volcanic cone. Sa
ludoshttps://www.facebook.com/photo.php?,,
http://www.facebook.com Avcan.
http://sosoceanos.blogspot.com.es/2012/05/imagenes-morfometricas-del-volcan.html
The blog is public therefore I have translated part of the comments posted on the blog .
The comments are courtesy of the SOS Oceanic Team posted on the link shown above.
,,1.-La mancha appears and disappears to the sway of the current 3D fields. The morning was and in the evening not (in March we thought the same, I was 13 and not 14)….When the current is strong, the pen is advectada/transported the layers and no signal appears in sup….2. The greenish color of the water this related to metallic elements that form chemical complex of that color (oxides). There is no sulfídrico… which is very good.3 Confirm that there are still ash in water (also was obvious)…. One of the magnetic triggers that activate the closure of sampling bottles (of 50 m) did not finish. It pervaded “magnetic” ash (metals). This has happened other times in previous outings. Ash, definitiviamente is (and will be for a little time) a good headache (ROVs, cameras, accurate morfometrías, oceanographic sensors)4.-The most indicative value is ph. 7 in the morning, 7.5 by to the afternoon (swell that mixes water and her – normalize-…). The normal ph in the Ocean (= Canary Islands) is basic (> 8.2). This ph slightly acid is indicative of a high content of CO2 in water (confirmed) and there is still some acidity in the water. In any case much less than 5 and oct/nov/Dec 11 peak… This explains the bubbling (gases-co2), the echo signal (gas + ash at depth). Also explain the greenish color (iron quelos), anoxia (ph under high CO2). Also the accumulation on surface of coastal pelagic juvenile fish would explain (confirmed) (sardines/mackerel…) – they passed through there – who suffered a small column of water (20-30 m width) with lack of O2 as pointed out octavio, acid ph, load of ash that adheres to the Gill arches and the eyes…Confirmed also the gaviotil feast… or they inmutan…It is also good sign… This confined to the environment – cone – local fish mortality, at the very least, this microfenómeno…and gulls (who see the stain the first) are responsible for metabolize these accidental loss of biomass/fish and turn them again into organic material that returns to the system… Strength, wind, sea and honor to all.,,
Magnitude M 5.2
Region NORTH OF HONDURAS
Date time 2012-05-03 18:08:06.0 UTC
Location 17.45 N ; 85.08 W
Depth 29 km
Distances 691 km SW Havanna (pop 2,163,824 ; local time 14:08:06.5 2012-05-03)
260 km NE La ceiba (pop 130,218 ; local time 12:08:06.5 2012-05-03)
223 km NE Tocoa (pop 30,785 ; local time 12:08:06.5 2012-05-03)
Some interesting quake patterh in Tjörnes zone. One at Theystareykjabunga, the central volcano itself, another at the end of the Húsavík fault – which seems to lead exactly into the middle of the a.m. central volcano and a ongoing earthquake series with hypo centers in the middle of the Skjálfandi (bay) and again in direct prolongation to the Húsavík fault. http://www.vedur.is/skjalftar-og-eldgos/jardskjalftar/tjornesbrot_litid/ Quakes are confirmed by IMO and the ones out in the Skjálfandi are at depth from 2.2 to around 6 km.
But the quakes would most probably be just tectonic, as they indicate the place of the Húsavík-Flatey Fault, one of the most important tectonic features of northern Iceland’s TFZ (Tjörnes Transform Zone).
@ Carl
VC post sent but I’m having trouble sending emails but-not-sending-em if you follow!
test post
Seems to work.
Keep me updated if it continues.
line space test
ditto test
ditto test
I’ve started using one of my Google addresses for some of the VC mail stuff.
Knowing how Google loves to look and track the nitty-gritty nuances of our lives and then sell that to market researchers….
… they are going to think I have multiple personality disorder. Interspersed with griping about invoices, service calls, best fixes and the occasional PDF… are some rather unrelated discussions about magma.
Bonus Plot… no specific reason. I had the data open in front of me so I figured I would toss one out.
The “Randy” folks might enjoy it.
It shows the general compositional family of the ejecta of a few eruptions… well, I didn’t note them on the plot, but you can see the SiO2 percentages as placed on the TAS diagram.
http://en.wikipedia.org/wiki/TAS_classification
Eh… here it is with the background from the Wikipedia link added. Helps to read the composition.
Use the types from the Wikilink to get the meaning of the abbreviations.
Quite an interesting increase in volcanic activity.
I am sure Katla will not stay silent over this.
No, and likely particulaily not, if she knew she will have multiple GPS measures of her bare (literally) sides this coming summer, overseen by “our” Q&A specialist Dr. Sigrún Hreinsdóttir.
Tremor event seems to be around Veidivotn or even Hamarinn. I want to reinforce there are several dams there. Could be noise due to that.
Otherwise, the event shows also a bit in Grimsfjall and Skrokkalda, which are both nearby. It smells like Veidivotn or somewhere around the dead zone. Could be Hamarinn, although if it would it would show better in Skrokkalda.
How long have those reservoirs been filled?
Is it possible that the increased mass of the lake could be influencing the seismicity?
Somewhere, out there, was a paper that discussed the distance that seismic activity due to increased mass of a lake could be detected. Something to do with the length of the lake. Not sure where that one is at.
Reservoir? Length, Thorisvatn is the largest “lake” on the island (both long and wide), its huge, almost like an complete Ocean to look at. And a look at vertical photo on Google Maps does belie its size. It never dries (its enlarged natural lake complex) but is only about 10 – 15 years “young”. I do not know of its current water level status, but if in encourages seismicity, do not think so, annually them few years I have watched IMO charts, I see no quakes around or under it. Weekly revised IMO charts can be consulted on this if me is not belived.
But the often mentioned SIL Vatnsfell is near this lake.
On the Nature of Reservoir-induced Seismicity
PRADEEP TALWANI
ftp://ftp.gps.caltech.edu/pub/avouac/Ge277-2012/readings/Talwani-Pageoph97.pdf
There has been talk about the influence of reservoirs on quake activity re. Hálslón at Kárahnjúkar in the eastern highlands of Iceland. This is regrettably in Icelandic. Páll Einarson thinks the quakes are due to magma movements. http://www.natturan.is/greinar/2367/
And on this I agree with Páll.
So do I. I live not too far from a rather large dam (Höljesdammen 130 MW/530 GWh about 50% greater than Vatnsfell power station), and there’s never been any quake activity associated with it. Nor can I recall any mention of such in connection with any of the really big power stations “up North”.
The Suorva and Harsprånget hydros had some small (below 1M) during the first five years after filling. If memory serves about 10 each. There was some associated tilt with the filling as it pushed down the bedrock.
But then Iceland is different then our ultra-thick, ultra hard swedish bedrock.
But, I do doubt that the very small Icelandic Hydropower plants would cause a lot of earthquakes and problems.
For the rest of the crowd, the difference would be like the largest Icelandic hydro-power dam was a VEI-1 and Suorva is a VEI-6. Two completely different sized beasts. One is a rabbit, one is an elephant. Guess who is louder 🙂
China has a VEI-8 dam… And that is causing a lot of problems with rock faultering due to the water-weight.
Overview about the power stations by their operating firm Landsvirkjun. http://www.landsvirkjun.com/operations/power-stations/
On Vatnsfell power station: http://www.landsvirkjun.com/operations/power-stations/vatnsfell-hydropower-station/nr/751
Curious, if we were to make assumptions about plinian eruptions, wouldn’t it be more likely that “tall” stratovolcanos that don’t have large exposed calderas be more likely to cause a vei 5+ eruption than a known powerful volcano with a significant sized caldera system.
If a stratovolcano located in an arc subduction zone is tall, has a symetrical cone shape, and no large previous caldera, it would seem it would be more probable to have a massive eruption than a similar stratovolcano without a decent sized caldera. My primary reasoning behind this thought process is that all notable “major” eruptions I can think of came from volcanos that were already “tall” and weren’t a depleted caldera system. Krakatoa was previously a Stratovolcano, as was Tambora, Santorini, Mazama, Novarupta, Pinatubo..and many others. Even St. Helens was like this.
So by this logic, couldn’t we assume with *relative* accuracy, we would need to wait for Krakatoa to re-build to at least a good degree of it’s previous height before it would start to re-erupt in any non dome building fashion? And furthermore, it’s seemed througout histories of most large known caldera systems, that even when they do “rebuild” and have their second, third, fourth major eruption, it always seems the first caldera forming eruption is the largest, and then the other eruption events start to dwindle in power (relatively speaking).
Also, what would this indicate for a volcano such as Merapi that supposedly has a very large magma chamber, no significantly visible sunken caldera, and a very active eruption cycle?
I’m not an expert, but perhaps someone who knows more than I do could chime in? Curious to know.
For what it’s worth, I didn’t mean to imply that Krakatoa, Tambora, etc aren’t still stratovolcanoes, but they’re now largely “sunken” compared to their previous symmetric conical shape. Especially if you were to compare something like Mazama (crater Lake) to it’s nearby cousin Rainier.
Personally, I understood what you were getting at. A stratovolcano has a pretty specific structure. The caldera collapse or lateral blast flank collapse doesn’t detract from how it was made. It may destroy the magma “chamber” but the chemicals and structure of it are pretty much intact… if scattered about a bit.
As for your ‘steadily decreasing size of the caldera’ idea… to me that’s iffy.
Underlying those towering volcanoes may be the remnant of a previous caldera event, the resurgent cone having completely filled the crater and taken over duties as ‘the volcano.’
As an example… Etna has enough bulk to hold two or three lesser volcanoes.
I see what you mean. More of what I was getting at isn’t that ALL eruptions would be lesser, but the “big” eruptions that periodically empty the magma chamber decrease (likely as the magma chamber solidifies and decreases in size). I’m not saying this is a fact of nature for all explosive stratovolcanoes, but it seems to be a trend at least.
Think about it..
Pinatubo’s recorded eruptions have seemed to grow weaker and weaker (not to say that they’re weak, but the 1992 eruption was slightly weaker than previous eruptions).
Similarly, the same can be said about the Campi Flegri volcanism (decreasing scale of large eruption events centered around the same system).
Even most of the large caldera hotspot “supervolcanic” systems seem to hold true to this. Yellowstone’s older deposits are increasingly larger than it’s newer deposits, and this holds true for Taupo, and most of the major caldera system (as a trend, not fact). Now, I definitely think the age and record has influence over this, and as we just learned w/ yellowstone, some eruptions may actually not be the same, but either way.
Recently, one of the lead researchers on Uturuncu volcano was featured on Eruptions… I can’t give you a link since Wired has probably the most apocryphal archiving system known to mankind… just a bit harder than Minoan ‘Linear A’ to figure out. So hard that Google just barfs up the most recent post from there.
Anyway, Uturuncu is exhibiting signs of being a ‘supervolcano.’ When asked how this was determined, he responded that it was a matter of the rate of heat flow to the base of the system. If it was high enough, it could keep the percentage of melt at a high value over time.
As you can see from a couple of my posts I am fiddling around with how fast heat dissipates in a system. (eventually this will turn into a glorious image across the dead zone that Carl will then write a nice post about.. mainly since I can’t really speak with any authority on the area)
What it boils down to, is how fast heat enters the system, and how fast it is removed from it. If a parcel of potential magma is at a high enough temp, it can sit idly by as until some event depressurizes the system. If it has had time to differentiate, or if it mixes and remobilizes older high silica material, it can be quite energetic when it crosses into the liquidous territory and decides it needs to get out.
The forcefulness that it has will determine how much of the ‘I’m not ready to erupt, but what the hell, I’ll go along too’ magma leaves also.
The key is leaving behind a void… a void that can not hold up the roof material.
Just the other day someone menioned that the center of Yellostone’s hotspot is not under the mountains to the NE of the last big eruption… but is under a relatively obscure town in Montana… to the NW of the last eruption.
That sort of makes sense. Tomography has indicated that the plume slopes off to the NW, and the Norris Basis, which had a flurry of increased geothermal activity in the last few years is more to the NW also.
Ultimately, it’s going to come down to the heat flux of the system.
Hi Cbus! As Lurking points out, it is the rate of heat accumulation that is decisive. It helps if you think of the conduits from Moho to magma chambers/sills as the volcano and the mountain on top as it’s surface expression or pile of dung. A tall, symmetrical cone with a tiny summit crater is a sign of nothing more than a functioning, unobstructed system of delivery.
Your idea that a volcano with a perfectly symmetrical etc is more likely to have a catastrophic eruption than a system which has previously had one is, alas, incorrect. Why? Because in the case of the former, the perfect mountain is an indication of regular evacuation of the bowels. Energy is not allowed to build up to the point where a very large eruption is possible.
The presence of a large caldera or calderas such as at Neberry or Rabaul is proof that the energy flow from moho and build up over time without relieving eruptions is sufficient to power a very large eruption. The “best” place to see this is New Zealand’s North Island which has had not less than eleven very large eruptions, nine VEI 7s and two VEI 8s, in the last 1.23 million years. Furthermore, the so-called “Oruanui eruption” 26.5 thousand years ago was a VEI 8 so your idea that the size of eruptions tends to diminish with time is not correct.
If you want to find which places are most likely to host very large eruptions in the future, look at systems located in a region with plenty of sustained volcanism which have had very large eruptions in the past and are considered “extinct” because they haven’t erupted in thousands, tens of thousands or even hundreds of thousands of years. Dr Shanaka da Silva did this with a volcano called Uturuncu in Bolivia, which had been active between 890,000 and 271,000 years ago and found an absolutely enormous rate of uplift over a wide area centered on the mountain. This is a system capable of a “super eruption”.
But do keep asking and expressing your thoughts and ideas! It is how we learn with the emphasis being that not only the asker of questions can learn from the process. Stop asking = stop learning. 🙂
I interpret this as you are talking about large eruptions above VEI-5.
You have a point and not in the same go.
The shape of the volcano is less important. But, potentially a non collapsed caldera could be closer to a caldera formation than a non calderad one. But, then it would need to meet quite a few conditions.
1. It would need a high rate of magmatic influx to sustain systemic pressure and build-up rate of the magma chamber.
2. It would have needed to either had frequent eruptions, or frequent magmatic emplacements. Probably both. Thusly it would have over time produced a large magma-chamber. This requires fairly frequent eruptions.
3. Then you need the volcano to not erupt for quite some time to have sufficient build up of systemic pressure through magmatic injections into the chamber. The injection would have to be of the right size to inflate the system, melt more surrounding rock, but not so large that it erupts. Over time then the top of the volcano would harden taking ever larger pressure loads.
4. A final massive magma intrusion that increases pressure untill the top cant take it..
There are probably today more volcanoes that has not calderad that fit the bill of point 1 to 4, than old volcanoes with a caldera.
Let us say that Etna stoped erupting for a thousand years? Hekla is probably just a few thousand years away, by all accounts she is the most likely to Caldera on Iceland together with Theistareykjarbunga (who also is a non-calderad volcano).
But, do not underestimate the already calderad volcanoes. Some of them is actually close to going caldera again.
Europes most probable caldera victims are Ischia, Bardarbunga and the two volcanoes under Langjökull.
Campi Flegrei and Laacher See is very far away still from going Caldera.
The caldera-forming eruptions centered on already existing volcanoes seem not to exceed VEI 6 very often and if they do, it’s minor VEI 7s. The truly big, caldera-forming eruptions – VEI 7-8 caldera eruptions proper – seem to do without any central volcano. Those that do form tend to do so along the edges of the caldera – Mammoth Mtn on Long Valley, Tarawera on Lake Taupo, Vesuvius and Ischia on Campi Flegrei etc.
I totally agree with you, I answered a bit more in general on caldera-formative events ranging from “vei”-5 and upwards.
the last two are having outlets so to speak, a Maori tradition says as long as it is ‘bubbling’ it is safe, if it stops you……
I am having a morning of ruminating.
Lurking’s bonus plots ( GeoLurking says:May 3, 2012 at 21:52) Got me looking and learning. The categorising of igneous rocks has changed dramatically since I first started studying geology. Here is a brief resume of the thinking in geology over the last 60 years (My experiences )
Around 19149 I distinctly remember being told that mountains were made as the hot Earth had shrunk. “Like a baked apple skin wrinkles, so the outside of the Earth has wrinkled”. I must have been so taken by this concept that it has stuck in my memory.
By 1955 I had met my geology mentor Mr. Edwin Beer.http://chat1960vintage.blogspot.co.uk/2011/05/fletcherising-d-fossils.html
.He was a geologist and went on to be one of the men who discovered rayon and it’s uses. He lived to 107 years . A truly amazing person. Because of his enthusiasm, I too wanted to be a Geologist. Back in those days women were not welcome in the profession and so I had to teach myself geology, My geography teacher kindly entered me for Cambridge “O” level Geology exam. I passed. Then there were far fewer rock categories. There were two types of igneous rock extrusive called lavas and intrusive such as gabbro, and granite and extrusive such pumice and basalt. The “Continental Drift” theory was accepted but poorly understood….it just “Happened”
I was fascinated by “Physical” geography. Back then this was a big part of the geography syllabus in schools. Every child knew how a volcano was formed and how Ice moulded the landscape.
Because I could not be a geologist I became a teacher, teaching Science and Geography.
Then in the 1970’s The geography syllabus changed….It became “Human” geography. I was disillusioned and could not enthuse over the geography syllabus It was then that I decided to specialise in teaching Biology (Ecology) ( I took a degree course in my “spare” time )!! Most physical geography was scrapped so that now in the UK There are two generations who were never really taught well about what goes on below our feet.
I am sorry this is a bit meandering…(I tend to think like this :D)…The above history may well explain the huge numbers of people in the UK (and maybe in the USA) today who are 2012ers or potential 2012ers.
Poorly educated people are more susceptible to believing those who are perceived as “Experts” without questioning . If they have no real education about Volcanoes, earthquakes and The Tectonic plate Theory then they will be fearful.
A lack of good education at school age concerning “Physical” geography leads to a poor adult concept of world wide “Events”.
As Icelandic children are taught about volcanoes and earthquakes at an early age, I am presuming the adult population is more understanding than say, East Coast Americans or UK citizens.
I wonder how many 2012ers are in Iceland? Maybe our icelandic friends can comment on this?
Ye Gods!!! This post has given me a major wrinkle crisis!!! I need another coffee.
Good call (e.g. more coffee) as well as the tale of shrinking scientific awareness. What is so sad is that from those lost generations the teachers of future generations are drawn, thus ignorance is self-perpetuating whereas increased awareness through learning must be sustained for many generations through conscious effort. The advances of the last centuries annihilated in one generation. The sacrifices made in the name of “equality” and “democracy” makes my blood boil.
<<<<<Hands Henri a strong cup of coffee to calm him down.
I agree. Somehow that flame of enthusiasm in education here in the UK has dwindled to a mediocre hotch potch of unquestioned facts. Exam requirements are to be able to hazard a guess at a multi choice question paper with a bit of project work, plagiarised from the internet.
Thanks! (Slips into over-coffee conversation) “I once read a fantasy series in which magic users were required to pass tests designed to kill those whose command of the craft was insufficient and constituted a danger not only to themselves but their surroundings. While putting to death may be too strong, prevention of what Ogden Nash describes as their raison-être might be a Very Good Thing indeed. Another Good Thing is that Lurking isn’t here yet or we’d be discussing the beneficial effects of organically derived fertilisers over a hastily sketched plot on a napkin.”
And that would be Raymond E. Feizts Magician series of books. 🙂
Alas, it’s Dragonlance by Margaret Weiss and Tracy Hickman in conjunction (or by the order of) TSR gaming.
Hi
Just in the middle of reading again the Daughter- servant-mistress of the empire serie right now after Magician. Coincidences ?
Drangonlance was Ok too.
Strange that this “kill the inept magicians” trend shows up everywhere isn’t it ?
Happily Rincewind survived….
Exactly. Those into litterature analysis will no doubt come to some hair-raising conclusions about what happened to the authors at the age of three. “Nice” men bringing gifts and all that for which the inept magician is a metaphor… 😯
in other words not much input from matter between the ears
I think there is not a lot of 2012ers in Iceland. For some reasons: Positive thinking (isl. “bjartsýni”) is the most influencial part of the mentality. Icelanders mostly still have a very positive image about the future and tend to believe “allt bjargast og réttast” (meaning: we will overcome difficulties in one way or other). This is contrary to all doomsday predictions. And, as the crisis of 2008, has not been so disastrous in the country as was believed in the beginning, this is reinforcing the positive aspects of future developments. And also the mentality may have helped to overcome a lot of the difficulties.
Also, I think, that the still predominant Lutheran Christianism is helping and keeping doomsday scenarios at bay, even if most of the Icelanders don’t go to church very often.
PS: I am no Icelander myself, but having lived for some years in Iceland and in an Icelandic family, I know the mentality. 🙂
Oh! I always thought you were Icelandic. 😀
Thank you, this is flattering! 🙂
Inge this is exactly the impression I get from the various sources I have here on the internet. A very proud and positive nation you are. We need this attitude to come back in Britain.
Hear! Hear!
See!?! Nothing good ever came with those pesky Frenchies in 1066!
(Get’s tools out to start building his longboat.)
I think the more pragmatic view is because of collective societal experience.
Historically, Iceland has already dealt with some pretty nasty volcanic stuff… stuff that hasn’t been lost to legend or lore. Just by living there, you can get an idea of just how nasty the nasty can be…. and that it’s immediate effects were relegated to the affected area. The longer term lack of food problem might be an issue, but can be worked out.
In other words… a ‘been there done that’ mentality.
Diana, what a wonderful bit of reminiscing. Appalling that women weren’t welcomed in the profession. What a mind-boggingly stupid loss of talent!!
I think I was a partial victim of that policy change. Up until the age of about 12 we had physical geography on the curriculum. After that it suddenly switched to human geography.
Had physical geography remained on the curriculum I may very well have ended up studying geomorphology or volcanology. As it was, it kind of slipped below the horizon.
Alas, I went to a very ‘progressive’ school in the 1960’s which had already switched to human geography. I loved physical geography at primary school and was looking forward to it – but we did the imports/exports of Rotterdam instead (that’s the only lesson I remember). I miserably failed my ‘O’ level. I always wanted to be an archaeologist, but girls didn’t go to university as we were expected to get married and raise a family. Meanwhile we could become secretaries or nurses. I chose the secretary route and skipped the family stuff. Eventually I got to university and became an archaeologist only to become a victim of the 2008 crash. The reason for this rambling post is to say that it’s never too late to learn. Here I am back at Volcanocafe school learning a huge amount every day! My school did teach me how to learn, I also learned not to trust what teachers told me and to find out things myself. This is why I’m sceptical of most things until I have learned about them from several sources. It’s also why I like to look things up!
I remember the imports and exports of Rotterdam.
I must though say that there where a few drawbacks to the physical geography only. But a mixture between physical and human geography would have been best. Then the kids would have learned what grows where, who lives where, what are the tradables, and how the hork it was all made. The old system was to much one way, the new system is to much swung the other way. Why the hork is humans incapable of going for the middle road that is best?
Ruminations…
What’s the point of being intimately familiar with the human geography of Rotterdam if you thinks it’s a tributary of the Mekong river in British Columbia?
Ot think that the Vikings were the first inhabitants of Britain and that Queen Victoria was reigning during WW2. 😀
Henrik, I said that both would be the best solution. Then you would know that fish from the Mekong Delta was delivered via ship (and that Maersk is the largest shipping line) to Rotterdam, and that it is trucked to Bredängsgatan 15 in Märsta so we could buy it in the shops…
And you would also know the fascinating story behind Kräkångerssnoret.
So you did but my reply was to Talla primarily. When people who have no idea about education, only high-falutin’ opinions (i.e. politicians), make decisions on education they always forget the basics without which higher skills become an exercise in futility, as I tried to illustrate. Before you can launch on human geography, you need a solid grounding in physical geography. Before you go on a holiday to a foreign country on your own, let alone decide to live there, you need to larn the language and that starts with the wearisome and time-consuming effort to learn the basic grammar and acquire a working vocabulary as well as pronunciation and spelling. Skipping physical geography in favour of human ditto is a bit like giving non-English native 10-year-olds the task of performing a play by Shakespeare in Mid-English.
Never, ever skip 101!
Ahem… host host…
I can not say that I have any grammar in Spanish…
Host host… I moved to Germany and studied there without knowing a single word of German. Guess if I was hungry for a few days.
Same when I moved the first time to spain.
I kind of like to throw myself to the wolves and see if I can outswim them.
But I do agree with you, one should learn the 101, it probably makes life easier.
I did learn English as a second language at school, was excellent at it, we migrated to Australia, on our way from country Victoria to Sydney, I went to the kiosk on the train platform to get some food for the journey, she couldn’t understand me or I her, so my husband ( he used to translate for the Americans) was annoyed and went himself, came back red faced without, so I went back with a piece of paper and wrote it down, she said oh… and I got food, it goes to show even speaking the ‘same’ language does not mean understanding it
Carl, Ursh, we’re not talking about the 0.1 percentile at the far right such as your good selves here. 😉
Henrik, I think you missed something about me… I am horribly lefty and a green-monster to. Rödgrön röra när den är som värst 😉
I am just a pragmatist regarding education, regardless of political colouring any politician will make an even greater ass out of the school.
Not political, Bell-curve you silly leg-before-wicket Swedish-person. And don’t try to obfuscate the issue by pretending to have misunderstood!
Actually I did misunderstand you this time…
But due to my interest (serious one actually) in improbabilistics I normally read the bell-curve only in the extreme left and right ends… To hell with the middle.
One of these days when I have time and energy I will write a book on the math of it. He was such a bloody genius really, but nobody gives him credit about being one.
Greatest philosopher of our time.
Henri – I’m with you on learning the basics. Currently I’m working with some twenty-somethings who have a very high opinion of themselves. They are very good at presentation – they can produce beautiful looking documents, but they don’t bother with the spellcheck, let alone editing for basic mistakes. Consequently I think they are a bit dim and they think I’m old-fashioned. One of them went to Mexico for her honeymoon and was told ‘by a real Mayan’ that the world would end in December. I have pointed out that this is unlikely but she tells me that as she has been to a beach hotel in Cancun and I have not, she knows more about it than I do. On the other hand, I know some really nice, intelligent twenty-somethings who are literate, numerate and have lively enquiring minds. I guess their schools were better. 🙂
Rofl. My step daughter thought Canada was near France because a Canadian girl on line spoke french!
@Carl 9:35 🙂
I think you are right about education or lack there off for the sprouting of 2012. The younger generation don’t seem to be to interested in good education, yet have everything at their disposal if they wanted to, I would have given a lot to have the opportunities which are available now, that is life
ARRRRRGH!!!
I f’kin’ hate WordPress. For some reason, everytime I post, the f’kin crap tics the box “Notify me of follow-up comments via email”
click the where it asks you for it, doesn’t do it anymore for me, must admit I fiddled around a bit
Sorry, left out vital information: Used to have it that way only today, WP decided it needed to send me loads of emails so it anulled my settings.
@ Henri
Just the same problem I had last night when I sent to Carl.
Also everything went ‘double-line-space’
I’ve had emails from WP as well
Just noticed – the ‘tick-box’ opposite Post Comment box below is ‘ready-ticked’ – dunno if that is the problem I’ll try unticking it!
Hullo Sir Alan! Long time, no see?
Yeah for blogs with very little trafic the follow up comments might be usefull
, but i had that set once during a Name that Lava Sheepy Dalek competition, arg, i turned it off asap. WordPress is changing things very often, and whenever that happens things are a little bit untidy often, but i am still glad Carl uses WordPress and not Disqus or something similar.
And as it looks the followupcomments are automatically clicked on, hm, not so good.
Yepp, I also have qualms about WP, problem is that the other options are actually far worse…
But if anyone finds a much better option and tell me about I would happily check it out and contemplate switching. Sofar everything else has even greater problems.
Most of these irritating wordpress problems disappear if you have a self hosted version on your own URL platform…. you just get left with the good bits.
@All So do you want to option to be notified about follow up comments, because i think i could remove that. But we better ask Carl.
I would be fore to have it removed. But if others want it to stay we could leave it.
Please leave your opinion all.
Off, for me. 🙂
Off please!
off thanks
It is gone now.
Just tested it on my testblogsoidontmessstuffup. I had to save the changes 5 times till it worked, but yeah this line can be removed if people want that.
Remove it.
What a wonderfull Dragon you are, have a truck-load of roasted sheep on the house.
Oh, and it seems I have the horking problem too, and I never ever asked for follow up mails… Sigh…
Blow it up and breath fire down the problem 🙂
Done.
Thank you, here is a tanker with wine to go with the truck of roasted sheep. 🙂
Not to be deleted now that I’ve commented on it though 🙂
I would rather not get notified of follow up comments, looking at the tickbox it’s pre-ticked for me despite not having used ticked it at any point previously (I’ve considered ticking it once in the last year, and eventually didn’t do it then either).
hmm that was just meant to be messing around based on ‘this’ not being very specific, runs scurrying away from the loud boom and blasts of flame as the magnificant drake Spica attacks the tickbox I was messing about too close to.
I never had so many emails!!! It looks like I actually have lots of friends. 😀
Which of course I have here but I really don’t want to be inundated with emails of comments I have already read!!!
Yup! My box was ticked for me too. Thanks for sorting this out.
<<<<<<<<Queues up outside the Sheepy Dalek Bar and waits for the doors to open.
Again the same strange behaviour in Vatnsfell station… http://hraun.vedur.is/ja/oroi/vat.gif
I noticed, this time the envelope (form of how it increases, stays, and then declines) is close to a massive intrusion.
But please Luisport, let us keep this to ourselves untill we are sure. We do not want to create scare stories un-necessarily untill we see any quakes in the area. People have better things to worry about than a 1 percent chance of a rifting eruption…
Ok, but this is a strange behaviour that i never see… yes, i hope it’s from the hydro-power plant! ;D
I hope so to.
If it had been a sub-duction zone it would have fit the bill perfectly for a slow quake.
It has already started to go back to normal levels.
Sure to be! I mean how else do you think the Ice Cream to be sold at convient points gets made?
Is there any of the Icelandic crowd who could call and ask if this is related to unusual hydro-power outlet volumes?
It is well possible that they let water into the river (Thjórsá). http://vmkerfi.vedur.is/vatn/VV_Frame.php?r=14668&load_graph=1&direct=1&station_id=222&station_name=Austurland&page_id=338
Can’t be because of temperatures rising. http://www.vedur.is/vedur/spar/stadaspar
Sorry, for some reasons I couldn’t set in the right link. Go to the link, I put in, so to: Suðurland: Þjórsá við Þjórsártún
Good spot Luis! Well done.
http://www.cenapred.unam.mx/popo/ImgPopoTlamacas.html Popo erupting now…
@Judith:
Still nothing to worry about, no dramatic increase in either tremor or earthquakes. So nothing pointing for a huge dramatic increase in eruption size.
Relax and continue packing 🙂
Thanks Carl .
Another quake swarm starting in Tjörnes fracture zone http://en.vedur.is/earthquakes-and-volcanism/earthquakes/tjornes-small/
The follow up comment line should be gone, Please let me know if anyone is having problems. And Carl you can still see all replies in the red number appearing in the top line and see all if you click on that. Thats not being shown for all others, just admins and i think editors.
Thanks, I am very happy that you got rid of it. I just threw out 60 mails from my other mailbox…
lol. Yeah till a few days ago you had to klick to recive those follow up comments, but that changed and it was set automatically. Glad to serve 😉
I do not get it, they do all the changes to help the mini-blogs out there. And they do silch to help the large mega-blogs with high hit-rate.
And that is stupid, it is on blogs like this they make any cash.
The average blog hosted on WP has 20 views and 1 comment a day. We hit between 3 to 10K views a day and between 150 and 500 comments per day…
One would think that they would be interested in the more rare problems we find since they after all wish to sell systems to the mega-blogs…
Oh no, dont you tell me you are no big fan of blogs like. I-am-so-imortant-i need to announce-to-the-world-i-need-to-pee-right-now. With some pics where you see some people get trashed and 5 accidental hits per month?
But yes you are right. The last changes are notgood for blogs with high hit rates.
When nothing is up one could read the introducation of wordpress how to become a wordpressadmin. It is mostly about, try to figure out what you want to write about.http://learn.wordpress.com/get-focused/
Is anybody watching the swarm WesternTurkey there have been 24 earthquakes since midnight .
http://www.emsc-csem.org/#2
Hello Judith, both the number, strength and location is normal. There is a swarm like this every couple of weeks there.
Regarding the problematic events at Vatnsfell SIL.
I have found the culprit. It is not Bárdarbunga, something to be thankfull for.
Only problem is that the activity shows at Fagurholmsmyri, JOK and GRF. And they showed well enough for me to triangulate the activity.
I still would say that I can be wrong about this, and even if I am not it is probably not going to amount to an eruption. But it seems to be that an emplacement happened today in the Grimsvötn southern fissure zone, and most likely another one took place earlier during the night.
I repeat, there is nothing to worry about as long as there is no earthquake swarms in the area, and they would be powerfull, no piddly one or two 1Ms… So, untill we see a large quake swarm start we should not worry people unduly I think.
Links:
As long as we don’t do a “Mayor of Naples”, I do agree. To judge by their track record of unparallelled excellence, Allmannavarnir are absolutely first class and will make information public as soon as it is judged impending and necessary.
Herein lies the seeds of a problem though. In order not to needlessly alarm or worry unduly, vital information may be witheld too long. This is especially true of a rare and imperfectly understood phenomenon that last occured long before science was at a stage where it could be studied or analysed at all.
If what Icelandic scientist have said; that Iceland may be entering a period of heightened activity, is true, it is hard to exclude the possibility of a repeat of the Eldgja, Veidivatn and Laki eruptions in the near, humanly forseeable future. In such a case, anomalous behaviour needs to be addressed publicly before people come to or jump to their own conclusions, especially with the “2012-er doomsday” mentality now prevalent and ever-present in the media.
I agree. 2012 is a sensitive year for these matters. Maybe in 2013, there is not so much need of being careful, but doomers are always ready to give their predictions, 2012 or not.
I think it is unlikely to have a 1783-sized fissure within the next decades, but it is instead more likely to have a 1862-sized fissure, maybe not in next 5 years, but probably within the next 50 years. I think the place to watch is either near Hamarinn or even Veidivotn, or north of Kistufell, so both sides of Bardarbunga.
The sad part Henrik is that the 2012ers almost stops me from being able to write what I think is happening.
I think we will have to come up with a codeword for Laki = Let us call it something that none of them will guess, I know, Nibiru…
Well, I think Nibiru had two “slow-slip tears” opening up for magmatic intrusions.
The part about it that has me intrigued, is that the Nibiru family (specifically the siblings to the North and West part of that area of the Nibiru universe) have a lot of seismicity that form a NW-SE trending lineament.
If the sprungur to the west of the ‘hooded one’ are any indication, this points at much of the stress being on the western end of the Nibiru path… an also tends to be in agreement with the GPS… or at least my take on the GPS.
Carl, regarding the Vatnsfell event, I think the source is closer to Hamarinn, further north of Grimsvotn fissure, because you look into it, the event shows better in Skrokkalda rather than the other 3 stations you mentioned. This gives me a feeling of something happening under Bardarbunga fissure.
However, it did happened an earthquake in SW Grimsvotn, so magma might have travelled there as well. But several earthquakes have been occuring all along Bardarbunga fissure, more than along Grimsvotn system. But as you said, nothing to worry, unless you see swarms there.
Also, seems to be more increased hydrothermal activity probably due to a dike.
No low frequency increase in tremor graphs. Still less than what happened last July at Hamarinn.
On that I can say definitly no. There is nothing showing for Hamarinn at all, and nothing for Bárdarbunga. It only shows south of Grimsvötn. I also had a clear signal today, and that also made it possible to get a loction.
I am trying to get a clear signal of depth, but it seems to be impossible.
So, it is definitly in the southern part of the Grimsvötn fissure system. Whatever it was, it is though over now.
South of GRF, where? In the direction of Esjufjöll or of Örefajökull? It wouldn’t surprise me as last year’s activity pre the May eruption showed quakes on two lines, one from Bardarbunga towards Örefajökull, the other from Hammarin towards Esjufjöll, intersecting at Grimsfjall.
It is south of Vatnajökull and west of Lakagigar eruption-fissures. But still well inside of Grimsvötn line. Think upper part of Laki 1 fissure and then go 10km west.
+/-5km accuracy.
But I know you don’t like Hamarinn Carl 😉
Last time I travelled close there, I could see the cauldrons on the glacier that appeared after the July 2011 event. Just like Katla event, no one is really sure whether it was a tiny eruption or not (authorities in Iceland have said that it was for Katla, but I am still not convinced). However it made me aware how Hamarinn is just as restless and active as Katla.
Eruptions can happen without breaking the ice; it happened for many hours during the 1996 Gjálp before breaking the ice. It took quite a while. So Fimmvorduhals sized eruptions will almost never break the glacier and go unconfirmed and undistinguished from glacial floods (and often will happen at the same time).
Hamarinn has one advantage, regardles of what it does or not does, it is noisy when it does it. The 2011 event regardless of it being a puny ass eruption or a Jökulhlaup with a subsiding icelake-roof (equally possible) was very noisy, and easy to spot.
I doubt that Hamarinn would do anything silently really.
http://hraun.vedur.is/ja/oroi/vat.gif what a jump!
It is though over, the activity finnished half an hour ago.