Eruptions in Indonesia and Costa Rica

Too bad we can't see what is going on. I think that is one of the things that made Eyjaf so interesting it we could watch what was happening. And, we had people in Iceland on the blog to communicate with.

I bet John Seach has a pic or two of Arenal. Not sure about Rinjani.

BTW, I plan to check here every day to see what is going on so I know it ain't over. :-D

Thanks, Erik.

@ Diane NCA I'm with you :)

Vanuatu volcanoes have awakened:
Watch the video!
http://www.iceagenow.com/Vanuatu_Volcanoes_have_Awakened.htm

Nice footage on the video. Mind you, I don't buy the arguments on the linked page or that Vanuatu is more active or represents any new threat, but nice shots of the volcanoes, no doubt.

Wow!!!! This J. Seach's video on Vanuatu is absolutely amazing. The guy is crazy! For those in Eyjaf's thread who were watching lava bombs from afar, they should take a look at this just to see Mr. Seach collecting pieces of incandescent pyroclast in a pail! No words to describe it. How come such a danger threatening Australian east-coast be monitored by instruments hidden on a plastic covered trash pan? Wow! Wow! I'd better go back to Iceland, to rest on Lady Eyjaf's lap.
http://au.tv.yahoo.com/sunday-night/video/-/watch/19084493

#4 Thank you Mr. Klementti. My heart is still beating from watching it on full screen. And even though I live on the other side of the world it's still scary.
Somehow your last post only came after I having placed mine, so, please take my apologies for freaking out.
I feel better when you say there's no reason for alarm here. But still, the idea of collecting lava bombs in a metal pail sounds terrifying. And I didn't know you can't run from hearing the explosion. That's surely the first thing I would do, no matter how much I would have been warned not to go. "Just watch the stars and see where they're heading to..." Are you kidding?
OK. Back to my lurker's safety.

Renato, John Seach is not exactly crazy. He just goes to get the info that is important for other volcanologists. There have been others who have done just what John is doing; risk their lives to learn more about volcanoes. He probably knows that one day, a volcano might kill him, but he learns a lot doing what he does.

Back in the '80s the Krafts went to volcanoes and they would get as close to an eruption as they dared and would camp by it. They gathered a lot of information for other volcanologists by their research. They averaged 12 eruptions/year. Unfortunately, they were killed by Uzen in '91. It is just as Boris has said; some volcanologists risk their lives so we can learn more about volcanoes.

#7 @Diane N CA: Sorry for the bad word choice. I didn't mean it in any detracting sense, much on the contrary. It's difficult to express our spontaneity in another language and I should be more careful in selecting words. I surely admire volcanologists, specially knowing that, most of the time, their work is underestimated. A good example is this seismologic "station" in Vanuatu, with no funding to support their studies.
Yes, I have heard about the Krafts and many others who died or suffered injuries when studying volcanoes. Their feats of courage (which I too clumsily named "crazy") actually put me to shame, and I come to this blog to hear from people like them and to learn from you how to be humble before nature's tremendous forces.
Thank you, Diane, and all the others, for your attention and patience that gave me so much throughout this "Eyjaf season" and take my apologies for my stupidities born from my excitement and awe inspired by these tremendous events.

@R. de Haan (#2). Thank you, very nice - and funny - footage. I particularly loved some of the journalist's comments. First, when John Seach talked about the possibility of tsunamis hitting Australia in two hours and said that in geologic time, they're common, the journalist looked at him and said in accusing and hurt tone of voice:

"Are you an alarmist?"

The second one was when they were walking on the edge and the journalist suddenly said in a matter-of-fact tone of voice:

"You're a bit mad, aren't ya mate."

Erik! I know John has his own blog, but why not invite him over for a guest feature or "Alan Boyle"-style Q&A on the Vanuatuan volcanoes? Please?

Amazing video! But when watching Seach & co. in the fallout zone of those bombs, spare a thought for the poor cameraman with them

Re: Arenal

Sadly, the Arenal Volcano(Costa Rica) does not have her own webcam but her sister, Turrialba, does. Click here to watch.It updates every 10 seconds:

http://www.ovsicori.una.ac.cr/vulcanologia/videoturri.html

You can follow Arenal's recent activity (seimicity) by scrolling down on this link:
http://www.ovsicori.una.ac.cr/sismologia/sismogramas_linea.htm

Here's another terrific collection of photos, not all volcanic, but liable to lead one off on winding net-trails...
http://scienceblogs.com/highlyallochthonous/2010/05/accretionary_wedge_…

I was at Arenal a few days ago, and the activity was limited to small but frequent glowing rockfalls. Took lots of pics but obviously I missed the big eruption!

For those commenting on John's Yasur video I can assure you that John is NOT crazy and that collecting fresh lava bombs at Yasur is a bit risky but surprisingly easy to do. All you have to do is go up there and wait for the odd one to land nearby, if you're keen.

Mt Baekdu, China/North Korea, shows signs of an eruption "within years".

http://www.koreatimes.co.kr/www/news/nation/2010/05/113_66491.html

Salient points: A M7.3 eq hit in 2002 and since then the mountain has gained 10cm in altitude and there are almost a hundred small quakes every day. In 2006, a Russian satellite recorded an increase in temperature and evergreens have begun to wither on its slopes.

According to the article, geologist Yoon Sung-hyo at Pusan National University says an eruption is "imminent" and tentatively sets a time frame of a couple of years.

(Isn't Google wonderful!)

@14 Interesting. It appears that Mt. Baekdu generated a VEI7 eruption around year 1000AD. So anything could be expected from this volcano.

Since that massive eruption, there are six (partly suspected) minor eruptions. Looking further back, it seems this volcano has a major eruption once every thousand years or so going back to 2160BC (+/-100years). If you look for it at the Smithsonian GVP site, it's listed under "Eastern China" as "Changbaishan" while Wiki has it as "Baekdu Mountain".

For those interested in "hard science", there's a paper from the Department of Earth System Sciences, Yonsei University, Seoul, concerning the 3mm per year inflation from 1992-98 available at:

http://earth.esa.int/workshops/fringe03/participants/123/paper_Fringe03…

Wow , what a video ! Thanks for the link those guys are nuts !
Talk about an adrenaline rush lol.The words 'balls' and 'steel' come to mind.

Combining two topics from this thread; here's John Seach#s take on Baekdu/Baitoushan:

http://www.volcanolive.com/baitoushan.html

It would be interesting to know (any history experts out there?) if the Baekdu and Billy Mitchell eruptions around the start of the 11th Century had any noticeable short-term global climate effects, e.g. historic records describing an unusually cold and wet summer

@mike don, #19. The Baekdu (Baitoushan) eruption, which occurred sometime around AD 1000 (dates range from ~970 to 1200 AD), is said to have had a strong but short-lived global climatic impact.

References:
Horn, S. & Schmincke, H.-U., 2000. Volatile emission during the eruption of Baitoushan Volcano (China/North Korea) ca. 969 AD. Bulletin of Volcanology, 61: 537-555; dx.doi.org/10.1007/s004450050004
Zhengfu, G., Jiaqi, L, Shuzen, S., Qiang, L., Huaiyu, H., Yunyan, N., 2002. The mass estimation of volatile emission during 1199â1200 AD eruption of Baitoushan volcano and its significance. Science in China, 45: 530-539; dx.doi.org/10.1360/02yd9055

Let's ask Kim Jong-Il if he can get some webcams installed at Baitoushan ^_^

@Renato, I think I know what you meant. Yeah, it does seem "crazy" to do something like John Seach does. I guess that film really got to you. He does get up close and personal with volcanoes and it takes someone special to be able to do that and not be totally scared out of your wits. BTW, you are smarter than you give yourself credit for. And your English is just fine!

@Gijs, not a chance! <-P

@MJKBK, I hope you are still on here and checking things out. I got mixed up in my memory, LOL. I have a neat, if old (1964) book called Earthquake Country and it is a Sunset Book. I found where it talks about the Devil's Punchbowl and it is not the Garlock Fault that comes in there it is the San Jacinto Fault. Here is what the book says:

"The Devil's Punchbowl formations also abut the San Jacinto Fault, which at this poin tis very near the San Andreas Fault."

I will do some more research on the fault systems and refresh my memory. I am also going to see if there is an updated version of this book because it is very good and is still worth having it because it has a lot of information about the San Andreas and other faults and a lot of pictures of what the faults can do.

I was also wrong about how far apart the Big Pine Fault is from the Garlock Fault. They are about six miles apart, not 25 miles apart. I don't know where I got that idea. :-}

Rinjani is another "interesting" volcano with its 6 x 8.5 km, oval-shaped Segara Anak caldera truncating the mountain much as Tambora is truncated by its 6 km wide summit caldera.

It's funny how "we" are drawn to volcanoes that in the past have had major eruptions. It is as if "we" expect the next one to be a similarly big one and are surprised to find that the majority of eruptions in their past have been, relatively speaking, minor affairs and the next one probably will not live up to "our expectations".

But if that is true, the converse must also be true. There must be volcanic systems that up to now have had a "mediocre" eruptive history where the big one is yet to happen such as the Eifel Volcanic field was some 13,000 years ago or Tambora in 1810. Does anyone know of any such candidates?

Hi Erik

Over here: http://earthobservatory.nasa.gov/NaturalHazards/view.php?id=44068 you say that "Volcanic particles can cool the planet by reflecting sunglight." But looking at the photo shown there, it would seem that the sooty-black cloud of particles from the volcano would *absorb* more sunlight then the normal white clouds beneath it. So that efect would be to increase temperatures on earth. The amount of temperature change is dependent on a host of factors such as composition of the ash particles (sooty-blackish or pale-gray), amount of the gases SO2 and CO2 (generally not considered "particles"), and how high that stuff gets.

Erik and/or Anyone,

Does anyone know of links with information on how to make sense of and interpret Tremor Plots, such as seen at http://hraun.vedur.is/ja/oroi/allarsort.html ? //

From many web links, I have studied how to interpret regular seismographs, such as seen here: http://www.isthisthingon.org/Yellowstone/daythumbs.php?glayout=1 ... but I have never seen "Tremor Plots" except at the Iceland site, and I can't find links on the web about how to read them. //

Can anyone find & ost links on how to interpret the Tremor Plots?

Erik and/or Anyone,

Does anyone know of links with information on how to make sense of and interpret Tremor Plots, such as seen at http://hraun.vedur.is/ja/oroi/allarsort.html ? //

From many web links, I have studied how to interpret regular seismographs, such as seen here: http://www.isthisthingon.org/Yellowstone/daythumbs.php?glayout=1 ... but I have never seen "Tremor Plots" except at the Iceland site, and I can't find links on the web about how to read them. //

Can anyone find & post links on how to interpret the Tremor Plots?

Boris: Thanks for the refs; I wonder if anyone has approached this from the opposite side, that is, a historian who has seen evidence of a brief global cooling event and looked for a cause?

Gijs: You might have a better chance of a webcam from the other side of the frontier, because Baekdu is partly in China

Henrik: I would suspect that the next caldera-forming eruption will come from a volcano which doesn't have a relatively recent caldera already in place, which makes Tambora pretty long odds against. A stratovolcano with no activity for centuries -perhaps none in historic time- would be more likely

Thanks for the Vanuatu video:

Can I just add that anyone who doesn't run for their life and just says 'Oh dear' when nearly hit by a volcanic bomb is a seriously cool bloke.

I think "Oh dear" would be a restrained response.

There are times when full on panic expletives are a bit hard to suppress.

@26 William - here's what I got a few threads ago - colors may not be the same...

The different colors in the tremor plots correspond to different frequency ranges - very much like audible noise, volcanic tremor has different frequencies. High frequency range (green) would correspond to extremely loud, hissing degassing, whereas the middle range (red) is what often accompanies Strombolian activity and the lower (blue) range is deeper, rumbling noise (for example of lava fountains). We've recently done work on volcanic tremor and different styles of eruptive activity at Etna, and the resulting paper is this: Behncke, Falsaperla, and Pecora, "Complex magma dynamics at Mount Etna revealed by seismic, thermal and volcanological data", Journal of Geophysical Research, vol. 114, B03211, dx.doi.org/10.1029/2008JB005882
You should try and download this from the Earth Prints web site of the INGV, if you're registered that shouldn't be a problem:
http://www.earth-prints.org/handle/2122/5293
Posted by: Boris Behncke, Catania, Italy | May 18, 2010 10:16 AM

@Diane NoCal and @Lurking, did you see my post for you in the other thread?

What I didn't remember last night was that Garry Hayes of Geotripper just did a series on the long valley caldera area.

This link points to the series:

http://geotripper.blogspot.com/search/label/Long%20Valley%20Caldera

Sorry for the double post, and if you'd already seen it-- ;-)

I thought that Eyja going into remission would calm the contributors to the postings down.

Instead I find myself being assailed with a blizzard of volcanoes, videos, alternative blogs and other info that I want to read, watch, and ponder on... I need more time in my life. Help.

@gordon

Turn..off..the..computer

Henrik, I have one that might be able to give a pretty good blast that, up until now, hasn't done that much: Mt. Lassen. It erupted last in 1915-17. It is a plug dome, but it was when it erupted and it can and probably will erupt again. No one knows when.

Another candidate for a caldera blast would be Mt. Shasta. Both are part of the Cascades, and in CA. Shasta is a little higher than 4667 meters and Lassen is higher than 3334 meters. I am not that good at converting from feet to meters, but that is about right. :-)

Elsewhere, I am not sure, but I think any of the Alaskan volcanoes could be candidates as Okmok has formed a caldera. How about Fuji?

@parclair [31]

Yes I did and I found it interesting, work issues came up and I haven't had time to get back and re-read it. I've had an idiot day... you know, one where you spend most of the day dodging and dealing with them. Personally I don't see the logic of asking someone if they need help in a store by four separate floor clerks in a space of 2 minutes and 20 feet of browsing a shelf. Just leave me alone so I can read the flipping label.

Nova (Public Broadcsating TV Program) is just airing now (East Coast US) "The Mystery of the Mega-volcano...."

Ding ding: just got an alert tweet from alaska_avo: "Thermal anomalies observed in satellite data over past few days suggest Cleveland Volcano has entered another period of unrest." Gonna go check it out.

ash on ocean part 3, for those interested: http://earthobservatory.nasa.gov/IOTD/view.php?id=44073

Here's the Cleveland update, FWIW:

Volcanic Activity Summary: Thermal anomalies observed in satellite data over the past few days suggest that Cleveland Volcano has entered another period of volcanic unrest. In the past, the presence of thermal anomalies at the summit has been followed by moderate ash bursts, sometimes to aircraft flight levels. Therefore, AVO is raising the Aviation Color Code to YELLOW and the Volcano Alert Level to ADVISORY.

The lack of a real-time seismic network at Cleveland means that AVO is unable to track local earthquake activity related to volcanic unrest. Unrest at Cleveland is frequent, and short-lived explosions with ash clouds or plumes that could exceed 20,000 ft above sea level can occur without warning and may go undetected on satellite imagery.

Hey Alaska ....
P.S Alaska has been quiet for some time now. They rarely go this long without 1 volcano on at least a yellow.
I think I will give the folks at AVO a ring and see if their webicorders are hooked up (just kidding of course )

Posted by: Dasnowskier | May 24, 2010 11:53 AM
LOLOLOL. Funny

I told ya so..
Take this all in good humor

@ 38 Doug mcl I remember the earlier questions about that, thanks for the post.

In the US, Central Time zone, Nova's program on the megavolcano is beginning right now on PBS.

#22, Diane, we had that Sunset "Earthquake Country" book, too! It may still be sitting on a bookshelf at my mom's house. I hold her responsible for my lifelong (55-year) fascination with volcanoes and earthquakes.

More on the Nova program Megavolcano at http://www.pbs.org/wgbh/nova/megavolcano/
Video preview (1:32 min.): http://www.pbs.org/wgbh/nova/preview/i_3312.html

Interview with a NASA climatologist:
What can a volcanic eruption that occurred almost 75,000 years ago teach us about today's world of air pollution, global warming, and climate change? Heaps, says Dr. Drew Shindell, a climatologist at NASA's Goddard Institute for Space Studies in New York.
http://www.pbs.org/wgbh/nova/megavolcano/shindell.html

Lake Toba in Indonesia is the largest volcanic lake in the world. In addition, it is the site of a supervolcanic eruption that occurred 69,000-77,000 years ago, a massive climate-changing event. The eruption is believed to have had a VEI intensity of 8. This is the largest known eruption anywhere on Earth in the last 25 million years. According to the Toba Catastrophe Theory, to which some anthropologists and archeologists subscribe, it had global consequences, killing most humans then alive and creating a population bottleneck in Central Eastern Africa and India that affected the genetic inheritance of all humans today....
http://en.wikipedia.org/wiki/Lake_Toba

Long Valley and Yellowstone are 2 of the 3 supervolcanoes in the US. http://en.wikipedia.org/wiki/Supervolcano

@29/Mike Don:

The Possible Climatic Impact in China of Iceland's Eldgjá Eruption Inferred from Historical Sources. (2005)
http://www.springerlink.com/content/w4tg1w57774q6605/

Based on Chinese historical sources, the possible climatic impact in China of the prolonged Eldgjá eruption starting around 934 AD was investigated. An extremely hot summer was reported in 934 AD; hundreds of people died of the intense heat of this summer in Luoyang, the capital of the Later Tang Empire (923â936 AD). Snowless (and possibly also mild) winters probably occurred successively following the Eldgjá eruption until 938 AD. In 939 AD, cold weather set in abruptly and lasted for about 3 years; whereas peak cooling occurred in 939AD. In the summer of 939 AD, it snowed in the southeast of the Inner Mongolia Plateau (about 40â44âN, 113â123âE). From 939AD to 941 AD, hard winters occurred successively in China. Worse, unprecedented drought and plague of locusts broke out in 942 AD and persisted in 943 AD. More than several hundred thousand people were starved to death. This catastrophe was at least partly responsible for the collapse of the Later Jin Dynasty in China. By comparison with the tree-ring evidence and uncovered European historical evidence, the spatial response to the Eldgjá eruption appeared to be complex, whereas hemispheric or global cooling occurred in 939â942 AD.'

The key to understanding truly catastrophic effects of volcanic eruptions lies not as much in the reported VEI of a single large eruption, but in the temporal clustering and critical location of repeated large eruptions, occurring over the span of several decades.

This appears to be the case with climate instability in the early-mid 10th century (beginning of the MWP), with unually long and severe droughts with persistent crop failures, and occasional massive flooding events. In Europe, it was the 'darkest of Dark Ages', and in China, it brought political upheaval, while in the Americas, the lowland Mayan culture collapsed.

@29/Mike Don:

The Possible Climatic Impact in China of Iceland's Eldgjá Eruption Inferred from Historical Sources. (2005)
http://www.springerlink.com/content/w4tg1w57774q6605/

Based on Chinese historical sources, the possible climatic impact in China of the prolonged Eldgjá eruption starting around 934 AD was investigated. An extremely hot summer was reported in 934 AD; hundreds of people died of the intense heat of this summer in Luoyang, the capital of the Later Tang Empire (923â936 AD). Snowless (and possibly also mild) winters probably occurred successively following the Eldgjá eruption until 938 AD. In 939 AD, cold weather set in abruptly and lasted for about 3 years; whereas peak cooling occurred in 939AD. In the summer of 939 AD, it snowed in the southeast of the Inner Mongolia Plateau (about 40â44âN, 113â123âE). From 939AD to 941 AD, hard winters occurred successively in China. Worse, unprecedented drought and plague of locusts broke out in 942 AD and persisted in 943 AD. More than several hundred thousand people were starved to death. This catastrophe was at least partly responsible for the collapse of the Later Jin Dynasty in China. By comparison with the tree-ring evidence and uncovered European historical evidence, the spatial response to the Eldgjá eruption appeared to be complex, whereas hemispheric or global cooling occurred in 939â942 AD.'

The key to understanding truly catastrophic effects of volcanic eruptions lies not as much in the reported VEI of a single large eruption, but in the temporal clustering and critical location of repeated large eruptions, occurring over the span of several decades.

This appears to be the case with climate instability in the early-mid 10th century (beginning of the MWP), with unually long and severe droughts with persistent crop failures, and occasional massive flooding events. In Europe, it was the 'darkest of Dark Ages', and in China, it brought political upheaval, while in the Americas, the lowland Mayan culture collapsed.

@ Diane & Mike: yeah, I know ;-) .

@ Henrik: maybe it would also be interesting to look at volcanoes or volcanic regions that haven't or have barely been active during the Holocene. Boris mentioned the Colli Albani (Italy, just south of Rome) some months ago as a volcano that might turn really dangerous in the future and I personally think that other morphologically young looking volcanoes in Italy are also worth looking at.

I'm not too worried about calderas however (the odds...), but volcanism in general in areas that haven't seen activity recent enough to be mentioned in the Global Volcanism Program really has my interest. Just download the Google Earth placemarks (volcano.si.edu/world/globallists.cfm?listpage=googleearth) if you haven't already and see how many young looking volcanoes haven't been marked just because they did not erupt or show serious signs of being just dormant during the Holocene.

One of my favourite volcanic regions is the Massif Central, France. The area hasn't seen an eruption for about 6.000 years (that's when Lac Pavin (maar) formed), so it is mentioned in the Global Volcanism Program. The area is huge and consists of a large number of volcanic fields and stratovolcanoes. The youngest field is the 'Chaîne des Puys' (formed mostly between 70.000 and 6.000 years B.P.) in the North of the Massif Central, although Lac Pavin and the surrounding very young volcanoes form a small field around 15 kilometers south of the Chaîne des Puys.

For those primarily interested in caldera volcanism: the Chaîne des Puys hasn't seen any, but just south of the Chaîne the massive Puy de Sancy stratovolcano/caldera and the Monts Dore caldera can be found. Especially the Monts Dore caldera (it erupted an estimated 8 cubic kilometers of rhyolitic materials) is significantly older (2.5 million years old) than the Chaîne des Puys, but Puy de Sancy has seen it's last activity around 250.000 years B.P. Even farther located to the south is the immense stratovolcano/caldera of the Cantal, where eruptions took place between 23 and 3 million years ago.

Maps and schematics of the Puy de Sancy and the Monts Dore: img197.imageshack.us/img197/3724/montsdorepuydesancy.jpg

No eruptions are expected to happen in the Massif Central any time soon, but the volcanic potential of the area is just as big as it is in the Eifel, if not bigger. I'm not referring to caldera forming eruptions. The region in which the city of Clermont-Ferrand (± 140.000 inhabitants) lies is known to have big earthquakes every few hundred years (>7.0 MMS are not uncommon to happen there from a geological point of view) and there are plenty of smaller (non-volcanic) quakes that occur in the area every now and then. Also a lot of CO2 is still being emitted and a lot of hot springs can be found in the Massif Central.

My guess is that if any new volcanism is to occur in the 'near' future (within now and a few thousand years) it will most likely happen in the area that was most recently active, so the Chaîne des Puys or the area around Lac Pavin. Although most of the eruptions in these regions have formed scoria cones, some of them have erupted violently due to the nature of the magma (trachytic to trachyandesitic) and/or because of a phreatomagmatic reaction (maar formation). Immediately east of the centre of the Chaîne des Puys lies the city of Clermont-Ferrand and the city itself has been built in a maar and between several scoria cones. To make things more interesting: the Chaîne des Puys has a number of lava domes with a violent past, of which the Puy de Dôme is the biggest and most well known of them all. It's a volcano that's actually two lava domes, of which one collapsed partially around 10.000 years ago and sent a large amount of pyroclastic materials down to where Clermont-Ferrand is located today.

Again: there appears to be no immediate threat from volcanism at the Massif Central, but it's one of the regions that is interesting to look at when it comes to eruptive activity where most people would not expect it.

#46 Thanks for the post. I have a question here (maybe another dumb one): what a 10 000 year span means in terms of earth cooling? In other words, is it fair to expect "extinct" volcanoes to come to life? I read in a recent post that volcanoes that haven't erupted in Holocene period are the ones considered extinct, but this should not be taken for granted. So what level of "extinction" is needed for a volcano to be considered safe? Should we worry, for instance, for ancient volcanism in Brazil, a land of very early activity in geological time? Thank you in advance for the answer.

@passerby [45]

Interesting. With bad weather comes dodgy resources, and with dodgy resources comes additional stresses on societies.

From Wikipedia:

... 907â960 was an era of political upheaval in China, between the fall of the Tang Dynasty and the founding of the Song Dynasty. During this period, five dynasties quickly succeeded one another in the north, and more than 12 independent states were established, mainly in the south. However, only ten are traditionally listed, hence the era's name, "Ten Kingdoms."

Today's Astronomy Picture of the Day (APOD) shows a time lapse video of a volcano:

http://antwrp.gsfc.nasa.gov/apod/astropix.html

It's the Cotopaxi volcano in Ecuador, but there is no eruption - just some beautiful night shots of the starts, clouds, and some mountain climbers. Still worthwhile to watch...

@Gijs (#46) Thank you! Do you remember that when we discussed the WEVF, EEVF and Laacher See, someone (was it you?) mentioned an area further east (Erzgebirge?) which was of greater concern since helium had started to seep out of the ground? Btw, from my years of slavishly following Le Tour, I remember that the cathedral of Clermont-Ferrand was built with the black basaltic rock from local quarries. It was very striking visually - upload.wikimedia.org/wikipedia/commons/thumb/4/41/Cathedrale_vue_de_montjuzet_detail.jpg/571px-Cathedrale_vue_de_montjuzet_detail.jpg

Passerby (#45), Lurking (#48) thank you! Famine or scarcity of resources brought on by changes in the weather or other conditions neccessary for the raising of crops certainly play a much larger part than is recognised in the standard works of History. The fall of the early Minoan civilisation and the French revolution are prime examples where volcanic interference is recognised as a progenitor. What about the "Fall of the (Western) Roman Empire"? Rome in it's thousand years of history shows several periods of violent turmoil, but after the Hun take-over, it didn't rise again but descended into turmoil.

Modern understanding of Attila is that he was not a Barbarian in the traditional sense but rather a higly educated man for his time. His goal was not the utter sack of Rome and the destruction of its empire, but rather for himself and his people to become part of it like other tribes before him. When this was denied, he took what he believed he had been promised.

Earlier, there have been references to a large eruption around this time and reports of a red sky over Rome. Could it be that in the turmoil of the times, the effect on agriculture has been missed and that scarcity of resources due to global effects of this large eruption (which I now, of course, cannot locate :o ) is what really caused the "barbarian unrest" that led to the demise of the Western Roman Empire?

I remember seeing a very interesting programme here on the poor climate in UK in about 536 -539 (and Europe) and its effects on development - leading possibly to the Dark Ages - as well as a reason for the name.

found this link. Very interesting.

http://www.ees1.lanl.gov/Wohletz/Krakatau.htm

@Gijs (#46) Thanks for the link to the montsdorepuydesancy.jpg. Auvergne is also one of my favorite places in France, especially the twin cones of Puy de Lassolas and Puy de la Vache, which produced an 18 km long lavaflow thus creating 2 lakes, Lac d'Aydat and Etang de la Cassiere: http://www.ac-nancy-metz.fr/pres-etab/colllesboudieres/act_peda/web-05… (in french) On the picture in the link they look a lot greener as I remember them, 10 years ago. Auvergne also reminds me of the Olot Volcanic field also known as the Garrotxa Volcanic Natural Park in Spain http://geographyfieldwork.com/garrotxa.htm
Another unknown volcano in France is the Volcan d'Aix en provence or Volcan de Beaulieu which erupted 17.5 million years ago. A pdf of the volcano can be found here: http://www.pgadomaines.com/chateaubeaulieu/iso_album/le_volcan.pdf (in french) The crater is now part of a vineyard.

Here is another link to the - same I hope - paper which Passerby was referring to in #44 and #45:

http://www.ieecas.cn/UploadFile/Download/2008/09/2008091861739765.pdf

"THE POSSIBLE CLIMATIC IMPACT IN CHINA OF ICELANDâS ELDGJ´A ERUPTION INFERRED FROM HISTORICAL SOURCES"

And the best of all this copy is for free... :P

@ Renato: when we look at Indonesia for example, there are a lot of volcanoes visible that have not been active during the Holocene. However, there are a lot of volcanoes over there that are still considered dormant or active. The cause for this volcanism to happen now and prior to the Holocene is subduction of the Australian plate under the Eurasian plate, and there is no reason to say that there's any less activity related to plate tectonics in that region now than there was before 10.000 years ago.

An example of volcanism that is truly extinct: in Scotland volcanism had occurred on a large scale throughout geological history, mainly during the early Devonian (Glencoe and Ben Nevis e.g.), the Carboniferous (Arthur's Seat) and early Tertiairy (Skye, Rum, Mull, Arran etc.). During all periods the cause for volcanism there has been different (subduction in different places during the Devonian and Carboniferous). What caused volcanism to occur there during the Tertiairy (a mantle plume or something similar) is now causing volcanism in Iceland, and because of plate tectonics this plume is not located anymore under what is now Scotland. There's also no more subduction in the area, so it's safe to say that none of the volcanoes that have formed there in the past will ever erupt again. Erosion (mainly glacial) has also done a lot of damage to what was left of the Scottish volcanoes, so nowadays the original morphology of the volcanic landscapes that have existed throughout time don't exist anymore.

My point is: I think it's fair to say that if the causes for volcanism to occur in a certain area are still there and are just as powerful as before, you may consider the entire region as potentially volcanically active. Ofcourse the biggest risk in most cases comes from volcanoes that have shown some signs of activity in 'recent' history (Holocene), but that does not necessarily mean that volcanoes that haven't erupted in the last 10.000 years or haven't shown any signs of being dormant (fumaroles e.g.) during that period won't ever erupt again.

@ Henrik: http://www.ufz.de/index.php?en=6141 ;-)

Ah, Le Tour... I'm a big cycling fan as well. I watch as many cycling races as possible, and I ride my racing bike as often as I can. The Tour is of course one of the most beautiful races in the world, and I'm glad to say that this year the Tour will start in Rotterdam, which is not far from where I live ^_^ .

The cathedral of Clermont-Ferrand is not only made of volcanic rocks, it is built on the eastern part in the tuff ring surrounding the maar of Clermont-Ferrand: img31.imageshack.us/img31/1940/coupedeclermontferrand.jpg

#53 @Gijs de Reijke:
Thank you very much. If the "major" cause (plate tectonics) is still there, activity remains a possibility, even though not showing evidence in a recent past. Of course, billions of years from now, Earth will have cooled enough and plates will no longer move, and volcanism will cease. I think I got it perfectly right. We tend to think of that "cooling" in our times because we don't have many huge examples like the large Icelandic basalts or Dekkan traps, but these are rare occurrences, which, however, still could happen (hopefully not while we're around). Thank yo once more.

Merlin 51: I have severe doubts about that theory (I've read Keys' book). Pre-1883 Krakatau already had a (largely submerged) caldera about, I think, 8km diameter; so the suggestion in that link is thst a sequence of events starting with (1) Paroxysmal eruption creating a 50km diameter caldera -we're talking Yellowstone size, here- (2) growth of a large Krakatau cone on the southern margin of that caldera (3) paroxysmal collapse of that cone to form the pre-1883 caldera and (4) growth of the historic Krakatau island with its three intra-caldera cones. All within a time frame of about 1000 years from 534AD to the arrival of Europeans in/about the 16th Century. Not credible.

If the known pre-1883 caldera at Krakatau was formed in 534 (I have my doubts) it MIGHT on its own have produced the climate effects, or two major eruptions within a short time (see Passerby 45 "temporal clustering, etc") could do the job: Rabaul and Alaska's Mt Churchill have both been suggested as possible other culprits

Passerby 45: and so we come back to Katla (Eldgja is part of the same system) ("We're all DOOMED!" - to quote the Dad's Army line) Interesting to show that you don't need a big, showy Plinian eruption column to produce global climate effects: a basalt fissure eruption without much of an eruption column at all will do the job.

@ Renato: plate tectonics (mainly subduction and divergence) or an anomaly in the Earth's mantle (like a mantle plume). In the case of the European Cenozoic Volcanic Province (ECVP), of which the Eifel and the Massif Central are part, there are anomalies in the mantle, although it is far from sure if these are 'classic' mantle plumes.

Well, "E" is "stinking up" rural Iceland per the latest Iceland Met updates:O)

Articles < Seismicity < Icelandic Meteorological office

Go to site map.

Eruption in Iceland - frequently asked questions
Update on activity
Eruption in Eyjafjallajökull, Iceland
Assessment 26 May 2010 18:10

There is still a considerable amount of steam coming from the crater. According to a webcamera in the morning, the plume was estimated at 2 km height a.s.l. (6600 ft). It is heading south with northerly wind.

But in the afternoon visibility has been poor, caused by ash that has been blown up around the volcano. Visibility in Vestmannaeyjar was 1 km and 2 km in Vatnsskarðshólar. Fine ash has been suspended. It does not go high up in the air, but covers the volcano so it can not be seen on webcameras.

Very little changes since yesterday. Since there is little activity, assessment will not be done daily. Next status report will be published on Friday 28th May.

Details in a status report issued collectively by the Icelandic Meteorological Office and the Institute of Earth Sciences 26 May at 17:00.
Assessment 26 May 2010 09:00

Conditions at the eruption site were similar yesterday at 17:00 as on 24 May, estimated through a webcamera and a flight over the volcano. Blue smog (sulfuric gases) could be seen and a strong smell was felt inside the airplane when flying south of the volcano. A group of scientists went to the crater and they could see a small blast of ash, but mostly it is steam that is formed above the crater that can be seen from distance.

Volcanic tremor was still more than before the eruption and has been rather steady the last couple of days, but small pulses, mostly on the lowest frequency (0.5-1.0 Hz), were detected on the earthquake stations around the volcano. Eleven earthquakes were detected under the volcano yesterday, but 8 earthquakes were detected there 24 May. No significant deformation at sites around Eyjafjallajökull in the last couple of days.

Details in a status report issued collectively by the Icelandic Meteorological Office and the Institute of Earth Sciences 25 May at 17:00.

@Renato I Silveira [54]

While the debate is still somewhat open as to the source of Earth's heat... remnants of formation or radioactive decay, here is something for you to chew on as you mull it over...

Back in 1972, an ore sample from the Oklo Mine in central Africa was analyzed by a lab in France. The odd part about it was that the radio isotopes seemed to indicate that the sample had already been through a nuclear reactor. With no known reactors present in central Africa, this lead to a bit of curiosity and further research was done.

It turns out that a naturally occurring nuclear reactor had formed due to the way that the sediments were laid down and with the addition of water to act as a moderator (slow the neutrons down so that they had a chance to react with other radioactive material)

From a Wikipedia Article:

The Oklo uranium ore deposits are the only known sites in which natural nuclear reactors existed. Other rich uranium ore bodies would also have had sufficient uranium to support nuclear reactions at that time, but the combination of uranium, water and physical conditions needed to support the chain reaction was unique to the Oklo ore bodies.

Da Link:

en.wikipedia.org/wiki/Oklo_natural_reactor

#57 #59
This is why I called this blog "addictive".
@Gijs de Reijke: Yes, I forgot to mention the mantle plumes, but no matter how much I read about them, still the whole picture comes to me quite weirdly. I was about to post more questions about them, but I think there's still a lot to be learned, even from experts.
@Lurking: In other words, Earth has it's own way to produce heat!!! That's awesome. I thought we should be running out of the original fuel from the big bang and now you come and tell me we have "natural reactors"? Wow! Repeat: Wow! Definitely a "living organism"?!!!

@ Renato: there are a lot of questions concerning mantle plumes. There are apparently different types of plumes. They do not all originate from the same depth and do not necessarily have a higher temperature than the surrounding mantle, so the causes of what can form these anomalies can be different.

The effect at the surface is in most places kind of the same, however. Usually a number of grabens form around the area that has the strongest upheaval, due to diverging stress caused by pressure from the anomaly, and all over the upheavaled area volcanism can occur over fault lines that lie over places where there is a high enough degree of partial melting. That is the case with most of the volcanic regions in the ECVP.

@Gijs de Reijke [61]

Something to add to the arsenal of different sources for plumes.

I read an article a few months ago that one of the consequences of the Farralon plate passing underneath North America as it dives deeper into the mantle, is the the Rio Grande rift... which will eventually eat the Rocky Mountains.

The northern most tip of that rift is located at about 39.076522° -106.184315°... or roughly 100 km South West of Denver. It's much slower than the African Rift valley... but it's there.

I think that as these old crust fragments ooze their way into the mantle, that they stir up currents and eddy's that we see as mantle plumes.

@ Lurking: there is indeed a theory about old plate fragments that have subducted into the Earth's mantle and cause 'currents' there. The same theory exists for the ECVP, although there is a lot of debate whether it is actually the case or not.

Under Europe the plumes go no deeper than the 660 km discontinuity (a difference in seismic velocity occurs at that depth), which could mean that the subducted plates form a so called 'slab graveyard' there. Movement of these old slabs is thought to cause more plastic mantle materials to pull together and rise to the surface because of its lesser density. This is a young theory though, and I guess it will take at least decades before any more 'certainty' can be given.

Another theory is that stress caused by the subduction of the African plate beneath the Eurasian plate did not only form the Alps, but is also causing more stress farther to the north and west. This is thought to cause pressure relief at shallow depths beneath the European continent, which could be a cause for more the more plastic mantle materials pull together and rise to the surface, much like in the other theory.

Whatever it is, plume-like structures have been detected under the ECVP by the use of mantle tomography.

#61 #62 #63
Sorry I had to go away from the computer and missed the interesting discussion. Always eager for more!!! Thanks for keeping me updated.
Difficult, for me, is to adjust my time scale to Earth's clock. This is what mostly amazes me about EQs and volcanoes. Suddenly everything just blows in minutes. But it's hard to figure out what goes in between these tremendous events.
As for the ECVP, I'd never heard of any mantle plumes underneath Europe before(but for Iceland, of course). I always thought it was all about subduction of African plate - Italy, Santorini, etc... (and yes, heard about micro-plates too). But that the Eifel Volcanic field could come to life again... wow! (I spent some time in German and new about it).
Well, I always thought it was much more simple to understand tectonic mechanisms here in S. America, where there are no such plumes involved - just the Nazca plate coming right underneath the continent. So, I don't have much to say, but... wow!

@birdseyeUSA re Tremor Plots, http://is.gd/cqNP1
Much thanks for the info. That was helpful.
William

@Renato #66

A few years ago there was a study done on what might happen if the Eifel volcanos would reawaken. It could get pretty nasty quickly e.g. the erupted material could dam the Rhein river, which would just make the mess even bigger.

At the time there was an article about it in the German news magazine "Der Spiegel"

http://www.spiegel.de/wissenschaft/natur/0,1518,466051,00.html

Unfortunately, it's in German only - but if you can read German it's very interesting stuff indeed.

What is up on Jon's helicorder?

@ 61 Lurking

Re: Eruptions and radio-active gases

Thanks for this information; very interesting.

I recently read about ozone (also radioactive)being trapped in the mantle and being capable of being released by volcanoes into the atmosphere during an eruption. I happened upon this info when I was researching the 'blue gas phenomemnon' at Eyjafjallajokull. So volcanoes destroy the ozone layer through SO2 emissions but occasionally can give a little back!!

Ozone, helium and radon are ALL radio-active gases capable of emission by volcanoes and the detection of large amounts of helium is a 'good indicator' of an imminent eruption.

Ozone for me was an unexpected find:scientists say that it was trapped there during "the Big Bang".

N.B. I came across this info. when looking up about blue gas.Ozone came up on the search as it is pale blue in colour but NO scientist has stated that it was infact released into the atmosphere by Eyjafjalljokull.

Have a look at Dagmar #25 on the new thread -

La Kat: Sorry, but ozone and helium aren't radioactive

@69: I would like to see the information source you mention reading. Mike, she is talking about He3/He4 ratio as an indicator of mantle-volcanic plume interaction.

New helium isotopic evidence of the Rajmahal volcanic plumes.
http://www.ias.ac.in/currsci/apr252009/1031.pdf

Not only is ozone not a deep earth isotope, but ozone, an atmospheric gas, is chemically reactive and is consumed by other reactive volcanic gas components.

@71 and 72

Thanks Passerby you saved me a job; Mike I will get you that paper because it really surprised me too. Ozone IS apparently down there - supposedly left over from The Big Bang- and is sometimes released according to the paper I read and it was a reputable source (i.e. scientific paper and not from a trashy mag!)

I have to find it now - help, I need my own relational information management system!!

Warning to self: never submit without source document links. LOL

@ 71 and 72

@ All

Re: My post no.69 (At present: possible rubbish! Please ignore until further research has been undertaken!!!)

Meanwhile as she starts to sift through files and stacks of literature, shaking head, and looking completely stressed out, please ignore my post. If one of you lovely people find it first, then post it here for me PLEASE!

A'la Kat

Check out 'radiogenic helium'

@Renato I Silveira (#62). What do you think provides the energy for mantle plumes? If the Earth's core was simply a cooling body of nickel-iron, how come it's still at some 5,700 Kelvin? When the Voyager spacecrafts got to Jupiter, they found that the planet radiated more energy than it received from the sun. The explanation given was nuclear processes in Jupiter's core. Even if Jupiter is 1047 times as massive as Earth, the bulk of that mass is in its atmosphere. Jupiter's core, ie what would be left if you stripped it of its atmosphere and liquid-to-metallic hydrogen ocean, is only 1½ times the size of Earth and estimated to be between 10 and 30 times as massive at around 30,000 degrees.

The odds are very much in favour of a "natural nuclear reactor" at the very heart of our planet where heavy element radioisotopes slowly decay. The half-life of uranium-238 is about 4.47 billion years, the same as the age of our planet, so only half of it has gone into or through the decay chain to stable elements.

Henrik: that idea has occurred to me too. After all, it seems logical for the heaviest elements to have sunk to the centre of the planet at its formation, and for there to be a region at the centre of the core with a high concentration of uranium/thorium. A very small region, they're not that common, but it wouldn't have to be especially big to have a very considerable heating effect.

By the way, we're talking about the formation of the Earth here, not the Big Bang; there's an eight billion year difference (or so, depending on the figures you use)

an estimated 3000 metric tons of helium are generated per year throughout the lithosphere.

http://en.wikipedia.org/wiki/Helium#Natural_abundance

7.6 QUAKE IN VANUATU....Tsunami warning in effect.

>7.6 QUAKE IN VANUATU

Yep. Right on schedule (for those of you who saw my post from two days ago).

Let's see if we get some answering shakes from our 'pressure-indicator' spots in Iceland.

#67 @Holger: Thanks for the article. I found it interesting when it mentions "ants serving as a warning". I'll have to read it again, with more time. I can speak German, but when it comes to scientific terms I need to be more cautious.
#76 #77 That means we are far away from cooling. And we humans (surely not us, right now) might be seeing a lot of huge volcanic events. Hope we'll be understanding them more accurately in the future as to prevent the impact. Scary! Thank you, Henrik and Mike don.

Hi All. Thanks for all the interesting discussion. I tried to read the 'slab' maps posted a couple of weeks back, for volcanic activity in the Mediterranean, looking for information on Majorca, which has a constant 30(?)ft high geyser in the middle, in a place called the Orangerie and much of the island is riddled with caves. What struck me most however was a strong smell of sulphur near the south coast in the early mornings. I have not found anything about any volcanism on or near Majorca, however. This was on a family holiday 2 years ago, when the bus driver said the smell was usual. Any thoughts? Does this fit in with the Spain and South of France hot spots? Could there be some venting of gases off-shore?

"By chance, I just found this:

Electric Ash Found in Eyjafjallajokull's Plume, Say UK Researchers
ScienceDaily (May 27, 2010) â In the first peer-reviewed scientific paper to be published about the Icelandic volcano since its eruption in April 2010, UK researchers write that the ash plume which hovered over Scotland carried a significant and self-renewing electric charge.
Read more:
http://www.sciencedaily.com/releases/2010/05/100527013219.htm
Journal Reference:
1.R G Harrison, K a Nicoll, Z Ulanowski, T A Mather. Self-charging of the Eyjafjallajökull volcanic ash plume. Environmental Research Letters, 2010; DOI: 10.1088/1748-9326/5/2/024004 "

This was originally posted by "Barbara, Germany" on another thread but is on topic for this thread so I have taken the liberty of copying and pasting it here as I think it will be of interest to others.

Hope you don't mind Barbara! Vielen Dank!

hi guys.

A big explosion ocurred last night at Pacaya Volcano, Guatemala. The international airport is closed and there are some reports of casualties. i know perfectly this volcano and i hope there were no tourists at that time around there, visiting the lava flows....Reports are talking about 10 cm ash fall in some parts. Keep watching.

Best Regards.
David Calvo.

I tried all day to think of some witty comment to write on your blog but all I got is âWar doesnât determine whoâs right. War determines whoâs left.â

hyave you all seen this: http://www.channelnewsasia.com/stories/afp_asiapacific/view/1089180/1/…

da*n the article have caused quite a discussion, have to think who i agree with.