Photographer: Robert Citron 1970, photograph taken right before the eruption. Courtesy Smithsonian Institution.
Hekla, a brief description
Hekla is probably Iceland’s most well know volcano. It is a fissure volcano, but during its history it has started more to resemble an elongated stratovolcano. It shares together with Grimsvötn the infamy of being the two most active volcanoes on Iceland.
Hekla is the least reliable volcano on the planet. It normally gives very little as a warning, during the last eruption the volcano started to have small quakes just a couple of hours before erupting. And those earthquakes were below the human threshold to notice. Even though there were a few small earthquakes a couple of hours before, it is more correct to say that the time from anything was noticeable until a column of ash started to form was 62 minutes. The same unpredictability goes for all recorded eruptions.
There have been reports that during the hours before an eruption there is a sulphuric smell to the northwest of the volcano, but I would not trust that as a definite sign. All it would take is a bit of wind and you would not notice it.
Hekla is the ashiest of Iceland’s volcanoes. Analysis of tephra finds in Scottish, Norwegian and Swedish peat bogs has lead to a calculation that two thirds of all ash in northern Europe comes from Hekla alone. This ashiness has helped researchers to narrow down when other volcanoes on Iceland has erupted. If you are looking at the Global Volcanism Program and see the word tephrochronology you can assume that it has been dated after comparing to the Hekla tephralayers. Hekla is normally producing andesitic basalts, not the normal tholeiitic basalts common to the other Icelandic rift volcanoes.
The tephras are normally very high in fluorine, and the eruptions emit large quantities of fluorine gas. This often causes large scale problems for the sheep industry since the grazing sheep gets severely affected or killed by acute fluoridosis.
Image: Icelandic Met Office. Harmonic tremoring following two small earthquakes west of Hekla.
Complexity
Hekla has one of the world’s most complex innards. 27 different researchers using different methods have found 13 different magma chambers ranging from 14 kilometers depth all the way to the boundary where the volcano starts to jut up from the surrounding ground. It is probably this intricate maze of chambers, dykes, tubes and whatnots that makes the volcano so explosive and quick to erupt.
Image: Iceland Met Office. The harmonic tremor spike recorded during the onset of eruption.
Eruptive behavior
Hekla is normally running in eruptive cycles. The current cycle started in 1947 with a VEI-4 eruption that caused large scale impact and fatalities. From 1970 onwards it has erupted about every 10 years with the exception of the 1980 and 1981 twin eruption.
Hekla’s eruptions normally has two phases, first a highly explosive phase producing a high ash column, then often follows a lava phase where either the entire fissure opens up, or parts of the flanking fissures open up. The length of the fissure that opens is normally a sign of how large the output of lava will be. The size of the lava output can range from anything from 0.1 cubic kilometer to several cubic kilometers. Hekla can show any of all known eruptive behaviors ranging from lahars to pyroclastic flows. Lava bombs are common during the initial explosive phase, pumice is not uncommon. Pretty much nothing can be ruled out during an eruption.
An eruption normally starts with a few earthquakes ranging between 1.7 and 2.0M, and then a large borehole transient is registered as the fissure is pulled apart. Harmonic tremoring then skyrocket as magma is explosively pushed up. During the last eruption magma travelled 3500 meters in less than 15 minutes. In 2000 the time from the recorded 1.7M earthquake to formation of the ash column was 62 minutes. This makes Hekla into the most dangerous volcano on the planet to be on top of. If you are on top and feel even the slightest earthquake, or minute tremoring, then you are dead.
Image: Icelandic Met Office. The clearest image of them all regarding the 2000 eruption. Stunning timeline, notice the transient in regard to the earthquakes. Do you think you would survive if you had been ontop when it went off?
Signs of the upcoming eruption
In 2006 the inflation of Hekla passed the level of inflation from before the 2000 eruption. This prompted IMO to send out a first warning stating that Hekla would erupt during the next 2 years. The rate of inflation has since been constant, and it has been calculated that the amount of magma in the system is now twice as large as before the 2000 eruption. The inflation first happened directly under Hekla in at least 3 different magma chambers. Since 2007 inflation also has occurred in either a cryptodome or a laterally removed chamber under Isakot/Búrfell.
During 2010 Hekla started to show a new feature, when earthquakes happened directly to the west of the volcano it started to show contractive borehole strainmeter transients, the same as recorded during the opening phase of the 2000 eruption, but on a smaller scale. This has been interpreted as being a sign of the volcano having reached critical systemic pressure.
During late 2010 Hekla started to have small earthquakes. So far they have been rather small, but they have consistently been followed by transients. This is rather worrisome since Hekla up until now has been considered to be rather seismically inert. On the seventh of July a 2+M quake was recorded together with aftershocks. This was followed with a very large transient reaching up the 1/3 of the energy recorded during the 2000 eruption. This prompted IMO to release a public warning that Hekla was about to erupt. Hekla though quieted down after that.
Other signs that have been reported during the last two years are reports of sulphuric smell; this was reported last during the July seven event. Another sign is reports of wells drying up around the volcano. This so far has been temporary only. But it is regarded as a sign of hydrothermal changes in the Hekla system.
There has also been recorded harmonic tremoring and magmatic signatures in all of the earthquakes during the last year. The last recorded episode of harmonic tremoring was during the last 24 hours.
Photographer: Robert Citron, courtesy Smithsonian Institution. Stunning image from the 1970 strombolian eruption of Hekla.
What would happen if an eruption occurred now?
If an eruption starts it would most likely follow the same behavior as before. A couple of hours of very week earthquakes ranging up towards 1M, then followed by one or two earthquakes ranging between 1.7 and 2.3M, a very large transient, harmonic tremor skyrocketing, and then within the end of the first couple of hours a massive ash column would form.
The probable size would be a large VEI-3 up to a sturdy VEI-4. The amount of magma inflation gives a high probability for the entire fissure opening up, with a slight likelihood for a fissure opening up towards Isakot/ Búrfell. Due to the larger than normal accumulation of magma in the system it is not unlikely that the effusive phase would produce about 1 cubic kilometer of lava, together with 0,5 cubic kilometer of tephra. But this is guesswork, and the eruption could be either smaller or larger. This is to be seen as a statistical average based on inflation rates.
Image: Icelandic Met Office. This is how a transient looks like. This was actually not a real transient and it was reset in the next update, but it is the best image I have how a transient actually looks like when it starts.
When could an eruption occur?
An eruption should actually already have happened, so most likely from a statistical standpoint, and with the signs of an upcoming eruption vectored in, we are anything from an hour, to some weeks away from an eruption. One should though recognize that predicting volcanoes is an impossible task. Icelandic Met Office has the best volcanologists on the planet, and they are very open with information (thank you!). During the 2000 eruption they actually hit the eruption on the minute, but it is rumored that it was a combination of tremendous skill and pure luck that made it possible. On the other hand, the skilled are normally lucky. But then, both of their last predictions for Hekla did not work. Why? Because Hekla is one of the most complex and unpredictable volcanoes in the world. But, I would be surprised if we got into June without an eruption having occurred.
Image: Icelandic Met Office. The real transient from the eruption. Notice the pattern with Búrfell falling sharply with all the others going up. The tell tale sign of Hekla ripping open.
Links:
Sadly the Hekluvöktun is not fully operational right now, but it is still the best source of information. I though hope that IMO will fix the page soon. It is not good that the borehole strainmeter plots have been down for months. It is after all the best way to see that an eruption is starting. Currently we have a larger chance by watching the cams.
http://hraun.vedur.is/ja/hekluvoktun/
http://hraun.vedur.is/ja/hekla/cam/cam.html
And a stark warning!
Do not, for any reason climb Hekla. If you do you are playing with your own life. I would also strongly suggest that you should stay at least 5 km away from the volcano. If you are within that distance you would probably not have time to get to safety. This is not a joke.
CARL
VolcanoCafé 
http://212.170.244.196/
Looks like lots of action again !
Anyone else watching are both stains bubbling now looks like the one in the background is aswell?
The one in the background is light mirroring out in the ocean. The sun that is.
OOps my eyes are not what they used to be sorry I thought it was bubbling again.
New vocation, anyone?
http://bgs.ac.uk/news/vacancies.html#ni_1652
Here is the video of yesterdays INVOLCAN / Guardia Civil flight above La Restinga:
Scientific flights INVOLCAN – POLICE HELICOPTER ON SUBMARINE VOLCANO AREA OF LA RESTINGA IN THE SOUTH OF EL HIERRO IN THE MORNING OF THE DAY JANUARY 2, 2012, MEASURING DISSOLVED GASES IN THE AIR ON THE ERUPTION ZONE AND TAKING THERMAL PICTURES . HIGH-RESOLUTION VIDEO CAMERA RECORDED WITH AUTOMATIC WATCH WHERE YOU CAN OUT OF MATERIALS bubbling CENÍCEOS, RESTINGA ALIGNED AND OFF THE SOUTH OF THE SAME. (Giggle slightly corrected by me, last lines too difficult.)
“VUELO CIENTÍFICO INVOLCAN – GUARDIA CIVIL HELICÓPTEROS SOBRE LA ZONA DEL VOLCÁN SUBMARINO DE LA RESTINGA, EN EL SUR DEL HIERRO, EN LA MAÑANA DEL DÍA 2 DE ENERO DE 2012, MIDIENDO LOS GASES DISUELTOS EN EL AIRE SOBRE LA ZONA DE ERUPCIÓN Y TOMANDO IMÁGENES TÉRMICAS. VIDEO EN ALTA RESOLUCIÓN GRABADO CON LA CÁMARA AUTOMÁTICA DONDE SE PUEDEN OBSERVAR BURBUJEOS Y SALIDA DE MATERIALES CENÍCEOS, ALINEADOS FRENTE A LA RESTINGA Y AL SUR DE LA MISMA.”
Well that kind of did it…
Bob is healthy, alive and kicking down there. No doubt about it.
I actually wonder how deep it is now, it looked quite a lot more shallow now than it did on the last video I watched.
My guess is that the decrease in tremoring is due to the secondary vents having closed down, and that the feeder up to Bob is now “unproblematic”. Less resistance in the feeder could very well explain diminishing tremor. And with less resistance I mean that the tube by now is fairly smooth and let a steady stream of gasses and solids through to the top of the vent.
Very nice video, Una Canaria, thank you brother from us!
Just dropped in to check whether the signal-to-noise ratio would be more tolerable to me after the “honeymoon” has gone…
Carl, I do have several of those Hengill-Hekla figures by Lurking saved on my PC.
I guess the noise ratio got better after me being gone for a month… 🙂
Please do send them, I am not sure that Lurking himself have them still.
I think Carl le Strange is right with that and too that the 1st underwater vídeo seems Alpìdo Armas´ tank aquarium.
Teh 2nd video with the jelly fish and final pulse or explosion and the video of the sientist flight are beeter…
My guess is there are a lot of gas, and Bob are playing a match with vents, conduits, magma cristalizated and so…
My guess is the maxim activity seismic and volcanic was around 11-18th november (dued by gases of the own eruption).
The high activity around december 15th was not dued by gases of the own eruption but gases of hydromagmatic and water reaction…
I think we are going downstairs in the energy level since november 11th.
I think Bob is in his last battle.
The last battle could be finished soon now or could be until March (this is my bet).
Probably we saw alteernating some dimishing of tremor and some seismic reactivation…
After tremor going upstairs and seismic activity going downstairs.
The last battle in energy, magma, and gases management.
Wow, I can´t help being awed by the sheer size and beauty of the stain when the helicopter flies over,,,, it is a very impressive show from Bob who I thought was taking his last breath a few days ago…
And now for something completely different – degassing in the Lacher See:
http://www.dailymail.co.uk/sciencetech/article-2081219/Is-super-volcano-Laacher-See-lake-Germany-blow.html#ixzz1iK2iVSAT
Fun fun fun, folks!
Ah, the probably most ill informed article in an english newspaper ever 🙂
Imagine there is a supervolcano beneath every pond with bubbles.
Lacher See is not a supervolcano by any stretch of the imagination. There are at least 7 volcanos in Iceland that has had larger eruption than Lacher See the last 10 000 years. And none of them are supervolcanos.
The closest volcano that could be labelled like that, and I do not like that label, would be Campo Flegreii in Italy.
And for those who wish, Erik Klemetti wrote the definite slaughter post on that article. He reached new heights of bashing in it… And the input from Giejs is probably the most defamatory I have ever seen anyone write about a journalist. Link up at the top to Eriks Eruptionsblog.
That post from Erik Klemetti made it onto the google science news front page 🙂
but somehow the google news algorithm didn’t include it in the thread under volcano news that related to the offending daily mail ‘article’.
I think google didn’t want to tar Eriks good name with associating him with Daily News in any way, even if he is doing a stunning thrasher 😉
There has been a 3.6 at Krysuvik – and a little swarm of tremors after it. Is this near a volcano?
Ah, a nice 3.6 magnitude quake in Krisuvik volcano. Might be the begining of an earthquake swarm.
Snap! 🙂
Alyson, that could explain why the uk is advertising for vulcanologist (see Peco Teco post at 10.22) – but as usual, so it seems in the scientific world, there is no rush to find someone to fill the post – applications for the vacancy are accepted up until 3rd Feb 2012…mind you, this article was in the Daily Mail,,,so it is more likely to be just a fairy tale!
There has been a Powerfull earthquake south of Krysúvik volcano.
As some of you know it is a volcano that could potentially erupt soon.
On the livefeed there is a marked magmatic component to the earthquake.
Here is the IMO quake list for the area
http://en.vedur.is/earthquakes-and-volcanism/earthquakes/reykjanespeninsula/#view=map
And here is the Kaldarsél SIL-station
We will have to wait and see if this will be the start of a real quake swarm.
The quake has been downgraded to a 3.4M at 99.0 percent by IMO. IMO works, wish IGN did that too… 🙂
And it seems to be building up to a quake swarm.
I would though want to say that even if there will be a quake swarm starting at Krysúvik volcano, it is still far from an eruption. Yes, there has been a lot of uplift since 2008, and it has had quite a lot of quake swarms since then, but there is nothing more really pointing to an iminent eruption.
Sofar I do not feel any need to write a run up blog post about Krysúvik since it will take at least ten more years before an eruption will start.
Unless of course other signs come into the picture, then I will write an article about Krysúvik.
I still though keap to my original statement, next volcano to go will be Hekla, even though some people are bending there asses backwards to not accept that 😉
There seems to be silly season on Iceland, another 3.4 just poped up in Tjörnes area. I though think that will be downgraded. These two quakes in Tjörnes is tectonic only, probably related to shifts in the microplate that is being pushed by Theistareykjarbunga that I told about in the post about that volcano.
http://en.vedur.is/earthquakes-and-volcanism/earthquakes/tjornes-small/#view=map
A short comment on automatic size from the SIL-network on Iceland.
As you have noticed they are normally down-graded by hand. And sometimes that downgrade is rather large. And even after they have been assesed by the duty technician by hand, it can still be changed when the day manager comes in and does her calculations. Thing is that it is almost divination to calculate an earthquake correctly. And sometimes two highly skilled geophycisists can come up with two different numbers.
So, that is why I am not that up to writing short blog posts about medium sized earthquakes on Iceland, because they will be changed in size at least once before I have set even the headline of the post.
And also, it would create a lot of nonsense blog posts that carry very little actual meaning. Of course I will write if there is a large earthquake, say above 4ish depending on where it is in Iceland. Or a large quake swarm have been going for a while so one might believe it could be a run up to an eruption. But otherwise I will just make small comments in the comment row…
So, sorry about not writing short posties all over about 2 quakes 🙂
Not to mention that different magnitude scales use different parts of the waveform. Some scales are related to the length of the coda (that part where the energy slowly trails off) others use the maximum transient over a segment of the waveform. That means that the different scales… though sort of close, have different slopes over their range.
SIL uses two different magnitudes in their catalog. M and ML. I’m not really sure what the hell “M” is based off of, but “ML” I have references on and can use to get energy values. I am also unsure of which of those two show up on the semi-live plot that everyone uses as a quick-look. I just go with the catalog (sveni-listi) (I may have misspelled it) since it has something I can make sense of.
The Tjörnes Fracture Zone quake has a couple of interesting features.
It does not show up well on the adjacent SIL-stations. Neither Grimsey, Hedinshofdi nor Leirhofn show it that well. If I look at Leirhofn it kind of looks more like a 2.5M quake.
But then comes the interesting thing, if I look at the 3 stations covering Theistareykjarbunga then I see it more clearly. I do not really understand why that is so, the signal is both more clear, stronger, and have an odd stretched out component. My guess is that the signal aquired a magmatic component when it entered the area around Theistareykjarbunga vast magma reservoir.
The phenomenon is most clear at Skildingaholshraun, the main Theistareykjarbunga SIL-station.
And while I was writing it was downgraded to a 3M. I still think it will be downgraded yet again.
Evening All, It’s lively here again after the festive holiday innit?
Here’s what I’ve been noodling around with lately… It shows all EQs since 22/11/11 (why 22/11/11? I hear you cry; ‘cos that particular set showed best something that I’d already noticed you hear me reply 😀
I know that there’s a very limited set to work with, especially as most EQs happened in El Golfo and in late november and also no depth information is shown…But if you’ll induldge me for a moment…
The green line shows an area with no reported EQS, apart from those outlined in blue (Tanaganasoga ont’ left, and (I’m guessing) another geologically recent cone on the right.) Note also a few other EQs below the NW-NE crescent ridge (also under previous cones I reckon…)
I know this only shows recent EQs but that’s sort of the point; if EQs show “breakthroughs,” then in a way older EQs are (perhaps) less relevant as time goes on.
http://tinypic.com/view.php?pic=2501onr&s=5
Cheers x
First, Happy New Year 2012 from “Chaine des Puys” to everybody !
… and a scientific and interested question !
Does anyone know, about El Hierro, what is the difference between “(SHZ)” (CHIE el hierro) and “(HHZ)” (EHIG la palma) ( = vertical, N/S, E/W component ? i mean the difference between S and H in hertz), and what means exactly “PSD” in frequency tremor ?
For me it’s spanish, not understood, so i try to understand in english !
Anyway have good time with volcanoes !
I will try to answer your question to the best of my ability, but there are some points of it I am not totally sure I understood.
I think you are asking about the SIL-station, ie the stations showing the tremor and not the GPS-stations.
CHIE is located on El Hierro, and EHIG is on the island of La Palma. So they are placed on different islands. EGOM for instance is La Gomera Island.
The you are asking a question that I think is related to GPS, vertical,N/S, E/W components. Sadly the IGN only show the combined value of horizontal movement. This is due to them being placed for trying to locate landslides, not magmatic movement. Because how ever you turn, the risk for lives is bigger from landslides than from an eruption on the Canarian Islands. Today they would probably have done things different, but now they are stuck with the combination equipment.
The things with S and H in herts is harder since I do not understand fully what you are talking about there. Please do rephrase the question and I will do a better answer.
PSD is the combined energy value in the frequency spectral plot. It tells how much energy there is in the various frequencies. It does a sum over time for each frequency line, not fancy really. But very informative.
Hope that this helped you?
Regards and welcome!
Carl
Thanks Carl,
It help about “PSD” (energy value vs frequency), even if we don’t know if the scale is always the same during 1 hour (!?), but it inform about difference about energy in frequence.
Otherwise it’s ok for CHIE and EHIG location, no problem, I look just tremor, not GPS.
I’m just trying to understood the difference between the scale : HHZ and SHZ.
You may be right when you say IGN looks about landslides, they have theyr own way of studies.
Anyway, if you consider tremor, it’s not the same if you try to compare vertical component, N/S or E/W component, or mixed horizontal component ?
I just try to understand if i can show the same parameter in El Hierro and La Palma !?
Best regards of an “ancient follower” of Iceland volcanoes
Problem I and many others in here have with IGN is that they have a tendency to rescaly things now and then, and that they never state the scale of energy (dB) on their various plot.
Yes, regarding the tremor they show a combined plot of the X, Y, Z axiss. At least that is the general assumption. Problem is that we do not know exactly what equipment they have, so it might be a 2-axiss SIL at some places, and 3-axiss in others. But sadly IGN does not give out info about that.
I would be weary of showing and comparing two different plots. CHIE for instance can rescale on an hourly basis. Highly annoying really.
Personally if I would be doing a comparison I would do it over the PSD plot since that does not change if a rescale has occured. Then you only have the problem with 2 or 3 axisses in the various plots being unknown. But that is a static problem, so those could be vectored in when you do the comparison.
Yep Carl,
Nothing possible to compare, i agree …
Thanks and have a good look on Icelandic volcanoes, I’m looking too.
There will be an article a week on an Icelandic volcano untill one of them explodes, then I am probably going to go nuts full stop. But untill that happens, there might pop in a volcano or twenty that I find interesting to write about.
And there are some articles coming from other posters that are quite out of this world.
Hope you will enjoy!
Here is the explanation of my interrogation.
From “Sismo” on http://www.come4news.com/l-le-volcan-el-hierro-apparition-imminente-du-panache-cyprissoide-672818 :
SHZ = sismomètre à courte période, haut gain, mesure de la composante verticale
HHZ = sismomètre à bande large, haut gain, mesure de la composante verticale
Pour la convention voir par exemple http://www.iris.edu/manuals/SEED_appA.htm
PSD = Power Spectral Density (voir par exemple http://fr.wikipedia.org/wiki/D…_puissance)
In french but I think easy to understand.
Anyway it’s not possible to compare El Hierro and La Palma in term of tremor …
Carl, I actually climbed Hekla last summer, as well as many icelanders and some tourists did it too.
But, yes, of course, it is dangerous. I saw myself how I was playing with death.
I hiked Hekla last week of last August, then next morning a 2.0 happened right under Hekla!
In that same month, I was climbing one afternoon in Thorsmork (near Eyjafjallajokull) when the whole ground shake for a while. A 3.1 had been recorded at that time in Katla! And back in 2010, I hiked Fimmvorduhals (after the eruption was over), and as I gazing over both Eyjafjallajokull and Myrdalsjokull glaciers, I felt a creepy earthquake coming from Katla! I must say volcanoes love me!
I strongly recommend against hiking Hekla. You need 90minutes if you run down the mountain, or 2 hours and a half, walking pace. I actually ran down the volcano just to see how fast it would be. The slopes are very easy to run down but extremely long.
I actually love that you tried the running time for Hekla. It kind of stops any argument that you can outrun an eruption there.
But I must admit that I would sure as hork not try it myself. Holding a Zumba class for rhinocorous ontop of Katla, oh yeah, I am your man, Hekla no way…
Did you feel the Krysúvik quake?
No I havent felt it. I am too far, north of Selfoss in Grimsnes.
But this area is well known by large earthquakes in 2000 and 2008.
I ran with the bulls at Spain’s Pamplona festival (San Fermin) once… From the beginning , about 50 metres from where they let the fire works off, about 40 metres from the Bulls. First thing; 7a.m ish, I wasn’t hungover, I was pissched!
Does that count? 🙂
I did it stone cold sober… After having planed to do it for a year.
Which one of us are nuttier?
Well,
If we’d both been gored, and Pamplona is the place to be gored if you’re going to anyway (The hospital is apparently excellent and specialises in Bovine traumatic injuries.)
Then I would have felt the initial agony less…
Whereas you would’ve been in a better state to undergo emergency surgery…
I wouldn’t do it again (for less than an million!) 😀
I was a bit faster back in ’91…
If anybody finds a video on Youtube I am the dude that rather quickly are in the front running like hell while an american looses his viriginity in the thick of it due to Bovine insertion of the third degree… I would also easily be picked out, I was the only one in studded sprint shoes.
Schtudded Schprint Schoes…
And you made it, you must’ve been schliding around more than the poor bovines…
I noticed that my choice of footwear was not the best, but what the heck, it is just to run faster to keap the balance!
If I redid it I would though use rubbers.
Wow, I had always wondered what makes those crazy young men run with the bulls in Pamplona. So here I have two people that can tell me. What on earth made you do it????
Scteve having his senses somewhat affected by alcohol may perhaps have given him some ‘Dutch courage’ (wonder why they call it that?) but Carl doing it plain cold sober, while no doubt safer, just makes it even less understandable. Do you just love being scared out of your wits?
In my case being a young man, with an oversized ego and trust in my own capacity to run faster than almost anyone, combine that with the total inabillity to calculate risks like falling while running, and you have the reason why I did it.
Please do note that I was a sprinter in my younger years… Do not do that run while being drunk, or if you are not seriously fast while running. I do not think doing a Schteve version of it is really the best way to go about it.
I’m from “down south.” The only running with the bulls that goes on around here is when the bull catches you crossing his pasture.
No cobblestone, no pavement, no place to duck to safety. Just open field. Just hope you can clear the fence on the first try.
😀
Its still being discussed about the dancing lights on the stain that were said to be from a ship.
Avcan FBCopied.
1. The international regulations to prevent the approaches in the sea, article 20 provides that ships shall be identified, night periods, with a few lights that can not be confused with other lights displayed on the ship.
2. Secondly, the same legal text provides the visibility of the navigation lights, reaching, for certain lights, a distance of 6 miles. This does not mean that not be seen at higher distances, always and when exceptional circumstances visibility but, by the experience that I have it is very unlikely that you can see the lights of an oil tanker that lies at a distance of 17 miles (31 km)(la_visibilidad_meteorológica_de_estas_luces,_en_general,_sin_tener_en_cuenta_fórmulas_relativas_a_la_curvatura_de_la_tierra)(, will be, about 13 miles) especially when there are disturbing elements of the visibility as vapor emanated by heating of water, removal of solid elements and others.
3. In order to make an idea with respect to visibility, in periods of high visibility in the Canary Islands and you can see Las Palmas with sharpness, it is impossible to see a light of a ship to that distance.
4. On the other hand, these lights change of intensity coming, at some point, to shut down that contained in the center of the “possible boat”. The navigation lights have no such changes in intensity. They are fixed intensity, and if the ship is fondead (the next item clarifies), it would have a range of 2 miles, it would be white. In any case and if you want to give veracity to the explanation of the docked ship, navigation lights that could be yellow, like these, would be those of towing.
5. Now, what is impossible from a technical point of view is that any ship which exist in the world could anchor 17 miles south of El Hierro. We have in mind that, being one of the characteristics of the funds of the Western Canary Islands practically non-existent platform continental, this distance can have depths of 2 or 3,000 meters and boats as which indicates you only have a length of chain of 420 meters maximum.
6. With regard to the localizatodo is more complicated than see it on the internet. The ship must have available the issuing equipment (AIS), in 25 W of power at a distance no greater than 60 miles of a relay. If there are no such circumstance, inter alia, not seen on screen.
In conclusion, in my opinion not he is a ship, although I can not inidicar if they are or not piroplastos, that I do not understand anything.
An expert in luminous intensity could clarify what the scope of lights that have a close to 100 candles light intensity.
Waiting for having clarified their doubts, yours “, I would like this to be able to contribute a little to the study of all the eruptive procesp, I like that when is a fact is corrobore(se_que_el_IGN_no_sabrá_de_barcos_pero_siempre_se_puede_informar_con_los_organismos_adecuados_e_informar_nos_a_todos), I would like to know the opinion of AVCAN, I would like to know the opinion of many experts who are here”… and I said, it transmitted here: is that a ship as well say experts in the sea. Now know if they were pyroclastic or it will not be experts in the field mission… or perhaps not is to know? Saludos a Tod @ s (Translated by Bing)
Just a short coment on 5…
There are ships available that can anchor at 3km depth. And I actually think one is close by, namely the new seafloor geosounding ship (that I have forgotten the name of). But what most ships like that do is to turn on the null-movement on the autopilat and the thrustors will “anchor” them within just a few centimeters of movement. It is much more exact than the old style anchors. With a system like this you can actually drill into the seafloor a kilometer or more down into the seafloor to do a test drill of oil-wells.
But no, I seriously doubt they would find it fun to do that out there since there is not reason for it.
Really depends.
While doing some exercises, we snuggled up with some merchants that were DIW overnight in order to blend in with the shipping.
As long as you have the set and drift down, cut the engines and post a watch to make sure you don’t drift away from where you want to be. Hoist a single black ball or the appropriate night time signal and you’re set. (vessel not under command)
I’ve made an animated gif with grabs from Movistar’s cams : it seems lights were really on the horizon … ( http://pix.toile-libre.org/upload/original/1324940970.gif )
– Track of the C-Whale supertanker on LocalizaTodo is “consistent” with the location where the lights were seen.
– The angular distance between bright spots (evaluated by comparing with elements of the La Restinga’s harbour on daylight pictures as reference) is also compatible with the length of the tanker (339 m) and its minimum distance to the coast (31 km) …
Only problem which remains : how a tanker may be “illuminated” like this ??? …
Perhaps an optical phenomenon like a mirage that would have amplified or focused the light emitted ??? … Not sure anyway …
lg, thanks for searching for an answer to this question!
It looked so much like burning gases, but that does not really make any sense, or does it?
I think that perhaps the crew were doing some work on deck that night, and had some high powered lights turned on. As for the smoky effect, that could be seeing the lights at a distance through fog or mist. Sometimes when you view the Movistar cams focused on La Restinga and Tigaday at night, the city lights are blurred and look like they could be flames, and those lights are much closer. Maybe it has to do with looking at a webcam picture instead of looking at the object directly. But it was fun while it lasted!
You must be right… if it had been flames, the tanker would have been damaged.
This morning, the ship is gone, this is a bubbling Bob to see! But why are anxious to Tenerife and El Hierro tremor graph? Is also associated with the noise?
Just seen smoking stones on the webcam.
http://212.170.244.196/
still smoking at 8:37
Still very active @ 9:02
Just thinking in my head its obvious Bob is still alive and kicking because of what we are seeing on the webcam at the moment
The IGN charts are showing harmonic tremors are very small so does this mean that the magma has found a new path without obstructions to follow but everyone should still keep their guard up because no one knows where this magma is going and what could still happen next?
Well, first problem here is that no one yet (fully) understands what causes harmonic tremor, actually… it is thought to be associated with magma moving (and most likely with bubble formation due to degassing, and then the interaction of the bubbles with the magma flow), but does not necessarily need to be so. And vice versa, there can be an eruption without harmonic tremor, too… so just don’t jump to any quick conclusions based on the IGN charts!
Almost anything currently flowing is erupted out of Bob, though, probably one does not need to have much worries about it going anywhere else, at the current stage.
Actually it is associated with high pressure. What I think has happened is that the feeder tube to Bob has whidened over time, especially at the narrow parts, and by now the magma and gasses has a fairly smoth ride. Simple hydrodynamics really.
I take visual evidence of activity any day over instrumental observations. An instrument can be affected by a lot of things really. And the CHIE is also compromised by IGNs rescalings, so watching steaming floaters have a much higher grade of trustworthiness than any tremor plot.
http://www.ustream.tv/channel/acn-media
The smoking stones can be seen more clearly on this webcam.
Thanks Judith, much better now it’s stopped zooming in and out. 🙂
Still a lot of smoking lava stones. The area where they appear seems bigger than before.
Many seagulls are active.
Boat just leaving harbour
I find that the tremor graphics of Fuerteventura, Lanzarote, La Gomera, La Palma and Gran Canaria are almost as intense as El Hierro. This has to do with noise?
No it has to do with CHIE being so downscaled that it is now useless since the tremor level is down. They should upscale it a notch. But I guess they do not want that since they believe it hurts tourism if the scale suddenly jumps up again.
And still smoking stones at 10:07. Lovely to see, proof with my own eyes that Bob still lives.
When you see the boat out there you get a much better idea of how large those waves are today. Also shows those smoking stones must be fairly large as some smoke for quite a long time despite a very strong wind.
Hello everyone, just had a quick peak at ustream and Bob is still producing stones. Back in a bit after coffee infusion, have to wake up.
Kiesewe
But where is this noise coming from do you think its something to do with Bob?
I mean, for example, when comparing these two graphs together. You can see in the intensity of the same or almost?
http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CHIE_2012-01-04&ver=s&estacion=CHIE&Anio=2012&Mes=01&Dia=04&tipo=1
http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=CFUE_2012-01-04&ver=s&estacion=CFUE&Anio=2012&Mes=01&Dia=04&tipo=1
I am here on Fuerteventura and we hardly have any wind at all do you think the rough seas around La Restinga could be anything to do with Bob.
I am feeling seasick just watching the boat !!!
Quite strong winds on south coast of Tenerife.
Heather
Glad to hear someone else has got the winds for a change instead of us then !
Hi Judith, we’ve had really strong winds for the last week, but still we have lovely sunshine to go with it. The winds do drop in the evening sometimes 🙂
This is the video capture of Bob at dawn, before the seas got too rough.
We have been having gales and today heavy cold rain in Northern England. It’s miserable. I need warm sunshine !
Thanks Diana for the video. Sorry to hear the English weather is lousy. I couldn’t stand it any longer and moved to Tenerife two years ago. Old age has to have some advantages.
Is that the strong wind, which makes itself felt? Why not in Tenerife, it is in the wind shadow?
Well I don’t know about wind shadow, but we always seem to have some wind and just lately it has made itself felt. It can get a lot stronger than it is today but still quite strong enough. I’ve not been down to the coast for a couple of days but it was pretty rough last week. I’m in Costa del Silencio on the southern tip of Tenerife.
Sorry this reply was for Kiese.
Mornin All, just noticed this, EQ at 537am, Mag 1.4:
Lots of smoking restingolitas to be seen ont webcams too.
judith says:
January 4, 2012 at 09:03
Just thinking in my head its obvious Bob is still alive and kicking because of what we are seeing on the webcam at the moment
The IGN charts are showing harmonic tremors are very small so does this mean that the magma has found a new path without obstructions to follow but everyone should still keep their guard up because no one knows where this magma is going and what could still happen next?
—————————————————————————————————————————–
My guess is there are a lot of gas, and Bob are playing a match with vents, conduits, 30% cristallized magma and so…
My guess is the maxim activity seismic and volcanic was around 11-18th november (dued by gases of the own eruption).
The high activity around december 15th was not dued by gases of the own eruption but gases of hydromagmatic and water reaction…
I think we are going downstairs in the energy level since november 11th.
I think Bob is in his last stage. (whit permision of the full moon).
The last battle could be finished soon now or could be until March (this is my bet).
Probably we saw alteernating some dimishing of tremor and some little seismic “reactivation”…
After tremor going upstairs and seismic activity going downstairs.
The last battle in energy, magma, and gases management.
I think this magma wont go more far of the actual open way…
The path of eruption will be the same place.
Low amplitude tremor is typicall of an lava efussion phase.
We must not be wrong thinking that low amplitude means low magma amounts.
Carlos, I would seriously suggest that you leave the full moon out of things.
A full moon does not have a higher gravitational pull than a waned moon.
And also, even if looking at the gravity curve the moon does not do jack hork to anything regarding volcanos and earthquakes.
Lurking did a very thorough try at proving that the moon can affect, and found squat. And after seeing how thorough he was I would say that the moon subject is dead as a door-knob. If there had been even a shread of influence he would have found it.
I think we should do a post on the subject… Lurking? How about you do the definite moon-post so we never have to explain it again?
The last co2 emission data was published on december 18th…
I would like to know the actual data…
Please, joke volta, as you have contact with the IGN CAP…
would you try to ask that to miss Blanco or miss López?
Thank you.
I want think that co2 dates have not been published dued to christmas hollydays…
And not dued by PEVOLCA didnt like the last measurements…
Involcan is the company who ususally publish the scientist flight videos and the co2 dates…
But in the last times I dont remember if was Involcan or was Canary´s Presidence who published the co2 dates offered by Involcan…
Thanks God Involcan is a private company, but they suffered too the force of the Pevolca´s law of silence…
Only the good dates (for tourism) are published quickly by Pevolca…
Hi Carl,
Just a quick note to mention that Jon seems to think it’s all quiet at Hekla
Edward 🙂
Good that you asked about that.
Jón and I have very different opinions about Hekla. And Jón is currently missing that the Hekluvöktun is inoperable. So I glean the data from the live feeds of Hekla instead.
I would also like to point out that there was activity in Hekla a couple of days ago, which prompted me to write a “before” article about Hekla. She is known to be close so I wanted to not be caught off guard. But, most likely it will take something from a few weeks, and up to a year before she blows. As you know I wrote that it is extremely hard to predict Heklas behaviour up untill the last two hours.
One thing one should remember is that Jóns reasoning is true at any given moment untill she erupts. He misses that Hekla is not going to give off real signs of eruption untill moments before erupting. He tries to predict Hekla like other volcanos, and that is just not possible.
But doing like he does and disregarding GPS inflation rates, transients, unusual quakes inside the system and so on is not good. I do not know why he does it, that you will have to ask him.
But, to clarify things, I am not saying that Hekla will erupt the next hour. I just state the odd scientific fact that she can erupt at any time withing two hours as long as the required set of trigger factors happen. Most of the factors are proven to be there allready. Problem is that we do not know what more is required. We will most likely know what that is after this eruption due to the vast amount of new equipment that has been installed around Hekla. One should acknowledge that IMO has more equipment, and more diverse equipment today around Hekla then around Katla. And for a good reason.
maybe Jon can be persuaded to comment here 🙂
Jón is as always welcome to do that.
Well I’ve asked – it’s always informative to see the two of you discussing things 🙂
And some good news!
Icelandic Met Office have started to fix the Hekluvöktun. It is not done finnished yet, but they are working on it.
I would like extend our official thanks to IMO for this, and all other hard work they are doing.
http://hraun.vedur.is/ja/hekluvoktun/
“Carlos, I would seriously suggest that you leave the full moon out of things.
A full moon does not have a higher gravitational pull than a waned moon.
And also, even if looking at the gravity curve the moon does not do jack hork to anything regarding volcanos and earthquakes.”
When I say “with the permision of the full moon” I forgot to say I was in mode ironic ON…
I´m sorry… hahaha
I hope when miss López talk about other planets she is talking about astronomy not about the planets´influence in Bob… hahahhahaha
Yesterday it was a pretty jupiter-moon conjuction… hahahahahaha
the opinion of Carmen Lopez (IGN): “The most influential are the tides, that people have mentioned, and of course will have a tidal component, because it is a fluid, just as there is an ocean tide, earth tide there. Even on land that is rigid has a tidal effect, and bulges and back again subject to the gravity of the moon, sun and even other planets and of course the magma is a fluid will be subject to a tidal effect of any other material of the earth has a tidal effect, but in this case was the effect certainly ruled over the rash. When there were more earthquakes there was some correlation between the seismicity with the tides, but one thing is that this phenomenon exists and another is to explain everything about it. We are here 24 hours and while there is light we observe the phenomenon on the surface and there was no more or less, in fact today (yesterday) brown spot appears larger than when the moon was full, what happens is that sometimes it is very nice to think that the moon alone can command a rash and not true.”
It seems to me that this observed ‘larger brown spot’ is fairly easily explained – and does not require any special ‘earth tide’ type ‘phenomenon’.
On the days on and around a full moon (or new moon) the tide goes out further when it’s low tide (and comes in higher when it’s high tide).
So during low tide during a full moon the vent is closer to the surface, than it reaches at any other time in the fortnight and the brown spot appears larger, probably you get a bit of that stain remaining for the rest of the day too – so it’s probably still a “larger” brown spot for the rest of the tidal cycle too.
We probably ought to get the tide times and expected rise and fall in sea level and factor that in to our observations on the webcam.
What is the tidal range at el hierro ?
looks like it’s not a very big tidal range max height +1.2 metres, min height -1.1 metres
http://www.tides4fishing.com/es/islas-canarias/puerto-de-la-estaca-el-hierro
the difference between a fairly quiet low tide (-0.3m) and at standard full moon low tide (-0.9m) is only 60cm which doesn’t seem like a lot to me
Sorry for not understanding the irony… I am coughing so hard today that I am getting stupid.
Sounds like you have a secondary chest infection underway. Hate to say I told you so….. Consider seeking anti-biotics from your doctor or add the zinc. A viral pneumonia at this stage is very unlikely. (may be a little too late for zinc to prevent the infection onset, but it still should help speed recovery from bacterial infection at this stage and prevent it developing into full blown secondary pneumonia)
According to he doctors I have contracted a common viral cold out of having a compromised imunodefense system from the flu. So it is a nogo on the antibiotics since they would not help me.
I am though taking some medication to loosen up the phlegm… And that makes me cough even more right now…
“The most influential are the tides, that people have mentioned, and of course will have a tidal component, because it is a fluid, just as there is an ocean tide, earth tide there. Even on land that is rigid has a tidal effect, and bulges and back again subject to the gravity of the moon, sun and even other planets and of course the magma is a fluid will be subject to a tidal effect of any other material of the earth has a tidal effect, but in this case was the effect certainly ruled over the rash. When there were more earthquakes there was some correlation between the seismicity with the tides, but one thing is that this phenomenon exists and another is to explain everything about it. We are here 24 hours and while there is light we observe the phenomenon on the surface and there was no more or less, in fact today (yesterday) brown spot appears larger than when the moon was full, what happens is that sometimes it is very nice to think that the moon alone can command a rash and not true.”
CARMEN LOPÈZ, IGN
This is the most unscientific piece of drivel I have ever read. To say something like this must be corroborated by evidence, and it is not. I have so far only seen one piece of evidence (and I have looked hard!) and that is what Lurking provided. And Lurkings very metodical and well done statistical plotting of tidal influence seriously kicked butt with what she is saying.
After reading this I wonder if she is an expert in Wherewolves and not a volcanologist. Please dear Godabunga, I hope this woman is a politician appointed, and not a scientist.
Actually i wanted to ask how big the tides are on El Hierro and how big their influence is, if Bob is still more then 100m under the surface, because the smoking restingolitas appear especially during the morning hours.
But there is really lot of action right now, so probably no tidal influence,….!
There exist nothing such as tidal influence on volcanoes.
The reason for this being that magma is way to viscous to have time to react to the rather fast moving tidal wave. Water has a high fluidical component, so it is much easier to move.
I have to invent a word here… Sloshabillity!
Think a bucket filled with a liquid here.
If you move a bucket of water it will easilly slosh around. If you then use exactly the same force on thick glue, you get less sloshability. To get the same sloshing with equal power per time unit you would hence need more time to get the same sloshing. And the tidal wave moves at the same speed through water as thick glue (magma) so the sloshabillity of magma will not have time to be activated by the tidal wave.
Hope I succeded with being clear on this.
Ah ok, i understand what you say but i guess i have used the wrong words for my question sorry for that.
Of course there is no influence on the vulcano itself. But what is the minimum depth for a Phreatomagmatic eruption? 100m under surface? Its about the pressure of the water, it cant vaporise if there is too much presure. So what is the difference between low tide and high tide on El Hierro? I have no idea it could be anything from 0.5m to 15m.
It should make a difference if Bob is 140m under surface at high tide or only 125m at low tide.
Now I understand better what you are after.
I guess there could be a very minimal difference in the hydrophreatic processes if there is slightly more or less water. But in reallity the difference is probably large of the height of various outlets in the went, than the rather small tidal height differences are.
Normal difference in open ocean is lower than close to the coast. My guess is that it is about 0,6m to 0,9 meters where Bob is. So not that much. Oh, and that would be Atlantic average out in the ocean.
They just might be easier to see in the morning & evening, depending on the angle of the Sun.
Hekla seems to be steaming. Probably an illusion as a reult of poor light and a shaky camera.
http://eldgos.mila.is/hekla/
This one looks healthier:
http://www.ruv.is/hekla
Carl, thanks for posting the link. I am trying to figure things out and I believe the spikes on the 4th ( blue line) are earthquakes. Is that right? http://hraun.vedur.is/ja/hekluvoktun/oroi_hau.html
Absolutly correct!
Tomorrow the 3 Magic men arriving to the city…
I whish you have a lot of presents…
Tonight the children write their letters of presents´petition and they introduce it in a mail-post carried in the back of the little donkeys.
I must go now to send our letters with my little son…
Cheers… And good coffe!
Looking at the moviestar cam I am wondering if Bob has got quite a bit closer to the surface. There seems to be constant white turbulance there and still loads of smoking stones coming up.
I have just got home so haven’t had a chance to check any other news on the eruption.
I’m seeing it too at the moment.
I still don’t believe Bob is going to die on us anytime soon.
It looked closer to the surface on that video that was presented yesterday taken from the Helicopter.
http://www.ign.es/ign/layoutIn/volcaSenalesAyerHoy.do#
Please could someone explain why all theislands graphs are showing some form of movements.
La Palma once again is showing the screw movements.
Tenerife has a strangle squiggle again and even Fuerteventura shows movement?
To be honest I do not think anyone understands why the activity-pattern has changed like this.
My guesspeculation (using both crystal ball & Magic Eightball here) is that we are seeing a shift in the hotspot as more magma is slowly oozing upwards. But once again, guessing here and I have no proof whatsoever for this.
Okay, after taking a closer look.
EOSO had an instrument failure.
EHIG is probably human interference.
CCAN is interesting, we have theorized that it is either something real, or something man made. I finally understood what is happening there, and I should have understood it a long time before. What we are seeing are either manmade or natural. But that is not important. Thing is that it is set to a very high gainstate, so when anything happens we get distorsion. The same as you get on an electrical guitarr when the gain is set high. CCAN is like that electrical guitar, any noise above the distorsion threshold is getting severely distorted, and we get that whacked up signal. It is so horkingly obvious really, I should have gotten this days ago…
EHIG looks to me resemble a lot like tremor associated with the new phenomenon of slow slip/ non-volcanic tremor.
Here’s EHIG today:
http://www.ign.es/ign/head/volcaSenalesAnterioresDia.do?nombreFichero=EHIG_2012-01-04&ver=s&estacion=EHIG&Anio=2012&Mes=01&Dia=04&tipo=1#
(click on the trace to expand the time scale).
And compare with fig 4 in this review:
ftp://ehzftp.wr.usgs.gov/jrubinstein/tremorreview.pdf
The review states ( quote) “Non-volcanic tremor is typically observed as longduration,
low-amplitude, non-impulsive seismic radiation most readily seen in the 1–10 Hz frequency band (Fig. 4, 5). The lack of easily identifiable features
makes it difficult to distinguish from cultural or environmental
noise ……….”
And KarenZ a couple of days back posted about recent GPS motion on La Palma.
When looking at the spectral plot things get much clearer. If you look at this link of the largest episode at EHIG you see a clear disconnect between the 2 and 3 Hz range. If there had been slow-slip happening.
But, that said I still believe in the slow-slip theory. It makes sense in so many ways for what is happening when a landslide would be under way. But I am not so sure we are seeing it on the tremor plot today.
http://www.ign.es/ign/head/volcaSenalesDiasAnterioresHora.do?nombreFichero=EHIG_2012-01-04_14-15&estacion=EHIG&Anio=2012&Mes=01&Dia=04&tipo=2&hora=14-15
The high frequency stuff is man-made on EHIG & CFUE – it is only present during the working day. The low frequency stuff (less than 2hz) is probably the signal from El Hierro.
I guess there is a similar explanation for CCAN as the pattern (with the exception of 01/01/2012 and 02/01/2012 ) repeats.
I don’t know why CVCB is showing downward deformation, especially as this appears to have been happening over a few weeks (http://www.seis.nagoya-u.ac.jp/sagiya/canary_gps/CVCB.pdf). I have not had the time to look for EQs as for north as La Palma.
But just had a quick search for EQs at La Palma since 19 July 2011 – can’t see any.
ER has posted a video of Yemen / Zubair group / Surtseyan eruption.
http://earthquake-report.com/2011/12/31/worldwide-volcano-news/