I wont waste space with a lengthy introduction … let me simply say that this post is down to you … our Readers, Commentators and Dragons … thank you!
As you read these musings please remember … we are not ‘experts’ … just imaginative and talented, self proclaimed Volcanoholics … and heck, if the IMO aren’t sure what the future holds … we can only wonder, watch and wait.
Firstly, I am not an expert. Secondly, I have not been following every last quake at Bardarbunga. Thirdly, I am playing devil’s advocate a bit. Lastly, and in the spirit of pure speculation, I absolutely reserve the right to completely change my thoughts at any time, for any reason!! ☺
So, right now, what do I think will happen at Bardarbunga? Nothing. The Nornahraun vents will continue to effuse and eventually the eruption will peter out and stop. When that may be is anyone’s guess.
Note that this has happened before. The current eruption site is a reactivation of a historic crater row, and this appears to be an obvious weak spot that has been exploited previously. I’m assuming that this crater row was the site of the 1797(?) eruption that created the Holuhraun lava field (and which was not accompanied by any central volcano eruption as far as I am aware). I have seen some places that attribute Holuhraun to the Askja system, although that would appear unlikely given current events.
I have yet to see any convincing evidence that the eruption is fed directly from the mantle, and therefore I don’t believe Nornahraun is a volcano in its own right.
For now I believe the eruption is being fed directly through the dyke from BB’s own chambers. As those chambers empty, so the caldera floor is subsiding – but hinged on the southern side so that it acts like a lowering trap door. That process may be enhanced by the effects of tectonic rifting as Bardarbunga’s caldera is also being pulled apart.
So far the subsidence has not been destabilising enough to the rock around the lowering trap door for the magma to find a route upwards from the chamber and, besides, the Nornahraun eruption is proving adequate in relieving the pressure on the system. If that pressure equalises, then the eruption will stop.
In that scenario what happens then, to my mind, is more interesting. If Nornahraun closes up, how will the inevitable ongoing pressure increase affect the central volcano? Now that the quakes and subsidence have no doubt destabilised the caldera floor to some extent, would a subsequent injection of magma then find it easier to erupt around the edges of the caldera floor, or even through it, rather than via a dyke?
Satellite image shows the original crater row that was reactivated by the current eruption. (Google Earth)
Leslie Robson Gompf
I don’t know if I am convinced that Holuhraun is acting as a pressure relief for Bardabunga, though the decrease in SO2 emissions from it over the last couple weeks would indicate to me that the amount of eruptible magma from wherever it is coming from is in the midst of being depleted. I cannot say if that magma is mantle (which I thought all along) or being forced out of Bardabunga.
I remain concerned with the punctuated deflation of Bardabunga. I believe I see several layers of hot stuff under Bardabunga from the earthquake plots. I wonder how much water from the caldera is making its way down near or into the magma chambers. Are we going to get to see a large steam-powered explosion when that mixing takes place? Perhaps. Maybe even likely. At worst, we may even see a proverbial “trap door caldera” which I equate to Bigfoot, the Boggy Creek Monster and Mothman in likelihood of being actual beasts, in action.
I look at newer earthquakes along the suspected dike out of Bardabunga as evidence that the rifting has not stopped nor has the flow of magma from the mantle. I don’t think what has already been erupted is enough to deplete the current rising blob much.
What do I predict? More lava out of Holuhraun; more earthquakes; and an explosion out of Bardabunga in the not so distant future.
GeoLurking enlightens Kilgharrah
GL “Bardabunga is a giant festering boil, sedately seeping out via Holuhraun. This could very well be the pace that the Deccan traps were erupting at until the Chicxulub impactor at a nearly antipodal position really ruptured the crust on the opposite side when the shock waves coalesced at the eruption site.“
K “Ummm … I have no idea what you are talking about … but if you say so I am sure its true (ish!)”
GL “Well… the gist of what I am saying, is that the Deccan Traps, which is coincidental with the demise of the dinosaurs, was likely just a fissure eruption happily spewing magma from a hotspot. The asteroid impact over in the Yukatan, of about 6 miles in diameter, it impacted with about 1.31 x 1024 Joules of energy, or about the equivalent to a magnitude 10.3 earthquake. When the shock front from that arrived at the Deccan Traps eruption from all angles simultaneously (antipodal), it probably ripped the ongoing fissure wide open and increased the magma flow.
In other words, it made an ordinary eruption much more vicious.
That the Deccan Traps were ongoing at the time of impact is certain. That the impactor arrived at the time of the K-T boundary is certain. There is some scientific argument about which one killed off the dinosaurs. My position is that it was the coincidence of two disasters that wiped out the life forms that didn’t survive the K-T extinction event.
Taking that a step further, should we get a monster impactor at the antipode to Iceland, it could be a repeat performance.”
K “Really? Ooh er …“
Is there going to be another shield volcano some years (or decades) down the road? This is a spot NE of Geysir, where a lot of holocene shield volcanoes are present, and where swarms and deep quakes often occur. Always in this spot!
Hilarious: Bardarbunga magma can’t erupt due to weight of ice cap, it moves an astonishing 1000km southeast and erupts somewhere in the middle of France. Why France is a question that will occupy geologists for the next 100 years.
Deeply serious (or maybe not): Holuhraun eruption continues until late January and then stops. Subsidience gradually slows down. A large earthquake takes place in Tjornes in 2015. A minor eruption near Askja follows in years ahead. By 2025 a large rifting episode starts at Veidivotn, at the same time, that aliens establish open contact with the human species, as wars and revolutions ravish across our world. Because of that epicness, no one will care about Veidivotn. In middle of these times, eruptions will occur also in Vatnsfjoll and northwest of Geysir.
Deeply philosophical: Why on Earth, did Iceland start to erupt much more often since I started living on top of it? I first came to Iceland in 2009 and shortly after Iceland erupted, then again in 2011 (Grimsvotn) and now Bardarbunga with a regional rifting event. It even behaved the way I said (a shield volcano at Holuhraun) Surely I must have some influence over it. What happens now that I will leave Iceland in end of January? Will Holuhraun also stop by then?
Mystical: Icelanders, or a part of them, believe in trolls. Some have even claimed to have talked to them. Trolls are lava rocks. Therefore, Holuhraun must be a mother of Trolls. 100 m3 of them every second. Are they all staring east facing the sunrise?
Enjoy your Friday.
OK, having watched dfm’s plots and read everything I can find I reach the conclusion
I have held for several weeks already and already committed myself to.
The plots in the caldera show eq activity North and South with a relatively calm space in the middle. Having observed Sil station data it is clear from some of them that during an eq the S wave is missing meaning the signal has passed through magma or ‘soft rock’ between its source and the Sil station. I believe there is a vast chamber or reservoir in this eq free zone which can be worked out by correlating the sil eq data lacking S waves. I have said this all along and the new accelerometer readings seem to support it also.
Studying the contour lines of Bardarbunga I see the weakest flank as being the steepest area on the Northwest, which also coincides with the site of the Vonaskard sil which has been consistently high since 16th August. This is where I believe any eruption from Bardarbunga will break out.
I also see evidence of a fissure connecting Bardarbunga with Tungnafellsjokull and therein lies a possible risk. I think following a major event we will see further activity along NVZ and WVZ. Also bearing in mind it has only been a few months since Hekla’s risk level was raised, this is another distinct possibility given the borehole strain reactions to eq activity in Bardarbunga and it lies at the tip of the Veiðivötn system.
I understand the scientific community has never witnessed this intensity of EQs without an eruption. And the sinking of the glacier is astonishing, and new in this day of modern instrumentation. What could expain this? I was on a mountain horse ranch some time ago and in the winter when the lake froze, it developed a leak and made for some fabulous ice skating (banked sides!). What if the rifting/grabens caused a leak in the lake below the glacier. Forget the melting of the bottom of the glacier. The top of the glacier would drop. There would be all kinds of deep explosions. But this immense glacier contains it because a lot of the action is too deep.
Where does the water go? Well there’s not that much of it compared to the size of the lake. It just has to drop 10’s of meters to see the ice sink. But this water has been percolating for centuries, so the upper magma chamber is already quite cold. So there wouldn’t be any explosions in the old, dead upper magma chamber.
Remember this is a very big glacier, offering a very good seal to the pressure cooker. So the 10km of rubble beneath the bottom can have lots of voids.
It hasn’t reached any rivers yet because the water flow is not on the surface.
We need to get Irpsit to call his friends and get an ice sonar to see what’s happening. surely someone has one that the IMO could borrow. (USGS?) I have friends!! Either that or we could ask for volunteers to dig a deep ice-fishing hole. People with short life expectancies and/or prisoners with time to Barder.
Obviously, some of the action to the side of the cauldron has magmatic origin, but even that could be influenced by the lake water.
I think we are seeing more dykes in ring faults, but I don’t think the bung is dropping.
The eruption currently is confined to Holuhraun. Barbardunga shows strong deflation and earthquake activity. How will this proceed? The plots below give some indication. The deflation is fitted with an exponential decay, with a change in time constant and zero level in early October. It fits extremely well. The earthquake activity (as energy in M3+ quakes) has been fitted with the same exponential. Since early October, this fits well. It indicates that the current earthquake activity is purely powered by the deflation – there is no indication for rising magma. But there was a major change in early October. What happened?
The exponential decay is easiest to understand as relaxation. It indicates that the magma chamber had emptied earlier, and that the mountain takes time to adjust to the reduced pressure from below.
The whole event started with movement at the MAR (rift). This is not actually under Barbardunga but runs some distance to the east. The expansion along the MAR lowered the pressure and set up a pressure gradient between Bardarbunga’s magma chamber and the MAR. The magma began to flow, created a path, and filled the MAR. Once in the MAR it turned North. Eventually it found a weakness which allowed it to reach the surface (twice, in fact).
I believe that the connection from the Barbardunga magma chamber to the MAR collapsed in early October. The collapse pushed more magma into the rift but stopped the outflow from, and re-increased the pressure in, Barbardunga. The total loss of magma was probably 3-6 cubic kilometers. Barbardunga may take months to come to rest and will subside by another ~10 meter but is unlikely to have a major eruption. Smaller eruptive events may be possible.
The magma has filled the rift, and created a new magma chamber in it. A fraction of this (typically 30%) will erupt. I think Holuhraun has already erupted quite a lot of this 30%. The eruption seems to be declining (based on how far the lava is seen to flow). I would expect it to erupt 1.5-2 cubic kilometer in total. It probably has produced a bit less than 1.5 cubic kilometers so far. It should stop in the next month or two – unless it can find a new source of magma! If it slows, the upflow may get blocked while the pressure is still significant. In that case a smaller eruption along the rift to the south may happen.
The rift has been heated by the magma. If this heat conducts into nearby, old magma chambers, it may cause some remelting. Small eruptions in nearby volcanoes cannot be excluded, in this case. So I would expect this episode to come to a close before spring. Bardarbunga will slowly re-inflate (this may take 50 years) and the rift will cool down. A small spring eruption in Askja may be possible.
This is my ten cents worth! In my experience, nature rarely pays much attention to me, though.
My conservative view is based on the premise that this has occurred before; but without the benefits that 21st century monitoring brings:
The Holuhraun craters are evidence for this, as is the presumably pre-existing graben between the Bardarbunga caldera and the eruption site.
The caldera itself has subsided before without a major eruption, the existence of the caldera itself tells us that. I realise that just because something has happened in one way before doesn’t mean it will happen exactly the same way next time, but my gut feeling tells me that:
The Nornahraun eruption will continue for a number of months until the whole system reaches a state of equilibrium and “rests” until the next time.
Recently, rises and falls in the tremor have been noted by IMO. Several interpretations have been made of this, I think the most precient is that of the pathway starting to close off. This would mean that the transients are in effect, “chuffing” of the flow trying to keep the pathway open. I’ve heard this time and again when a ship getting underway sounds it’s whistle. Water condensate that has collected in the steam line is blown out and until it is completely removed, you get a wavering of the sound. I think the worst one was when a stream of hot rusty water was blown all over the flying bridge, causing the forward lookout and signalmen to go scrambling for cover.
In Holuhraun’s case, its the slow blocking off of free flow. To me, this signifies a “hammer” effect beginning to form that is actually causing pulses of back pressure all along the magmatic system. Whether there is enough overall pressure to open up a new pathway has yet to be seen, but I think it is possible for a new vent to open elsewhere along the dike or along one of the ring faults. If it’s a ringfault breach, there could be a smallish eruption at the main vent… but not spectacular. There is even a possiblity that a reawakening could happen along the Gjalp fissure since it is the youngest and most recently active Bardabunga feature. Since the dike intruded into the Grimsvotn swarm, that system is also in play, and I can’t rule out something showing up there. Grimsvotn’s last show was in 2011, and is much fresher than Gjalp, and therefore weaker. This is only a possibility if one of Grimsvotn’s chambers got in on the dike intrusion from Bardabuna. No, I don’t have any data backing that up, just ruminating. Though GPS data from Grimsvotn would be indicative if it has merit..
Volcanic inspirations: the plays of William Shakespeare
Volcanoes have long been popular with writers. The modern English author Robert Harris set a story in the shadow of Pompei. The 19th century poet Matthew Arnold based a poem on Etna. Jules Verne used the Iceland volcanoes into his story. Much further back, the writers of the Edda clearly were inspired by volcanoes. A 9000 year old mural in Turkey is believed to depict a volcanic eruption. The bible includes references to apparent volcanic events. Frankenstein, not itself about volcanoes, was written in the gloom of Tambora’s eruption. Even writers who did not directly write about volcanoes were fascinated by them and became avid volcano watchers. Charles Dickens is forever associated with Vesuvius and Mark Twain with Kilauea. William Shakespeare and Pliny the Elder are other examples of historic volcano watchers.
Shakespeare was known for using hidden references, possibly even hiding his name in the King James translation of the Bible. His personal interests are equally hidden in many of his plays. Only recently has it been discovered that these interests included volcanoes. He lived at the time of the Santorini eruption (1570), Hekla (1594) and Katla/Eyjafjallajökull (1612).
Early drafts of his plays show his volcanic inspirations, where some of his most famous phrases appear slightly different. Here are a few examples, with their probable origins.
On the Hekla eruption:
“The lady doth erupt too much, methinks”
(This was later adapted for use in Hamlet, as “The lady doth protest too much, methinks”)
“Yet do I fear thy nature; It is too full o’ the magma of human kindness”
On other Icelandic eruptions:
“What’s in a name? That which we call Eyjafjallajokulla by any other name would explode as sweet” (after the 1612 eruption of this volcano)
“Double, double, toil and trouble; Fire burn, and caldera bubble”
“The course of true lava never did run smooth”
(Both are believed to be about the Katla eruption, also 1612)
“fair fires but foul fumes”
(It is not know exactly which Icelandic volcano this referred to)
“Friends, Romans, countrymen, lend me your ears; I come to bury Pompei, not to raise it”
Again, clearly a reference to a volcanic eruption but not known which one:
“Off with its head!”
Shakespeare was an early convert to the idea that volcanoes affect weather. Thus he wrote:
“Now is the winter of our discontent”
Finally, Shakespeare was a prolific blogger (‘Quaking Bill’) and knew the early Volcano Cafe well. As he wrote there:
“I like this place and willingly could waste my time in it”
So what did Shakespeare expect of Bardarbunga? He clearly knew that volcanoes need to inflate before eruption.
About Bardarbunga, Shakespeare wrote:
“I’ll not budge an inch”
It is therefore inferred that the Bard did not expect Bardarbunga to erupt.
Thus the whirligig of time brings in his revenges.
Are the magma chambers of Bárðarbunga being emptied to fuel the fires at Holuhraun or is she being fed by the mantle?
It seems to me, long time lurker, addicted amateur and avid reader of all that VolcanoCafe has to say, that we need know the definitive answer to this question. In the absense of that I prefer not to speculate on the future but to sit back and watch in awe as the events unfold!
A sincere thank you to everyone who has contributed to this post.