That tricksy volcanic system - waiting for us to fall asleep before giving us a new, bigger eruption! For last night light once again appeared on the webcams pointing at Holuhraun, where the large magma dike has been fracturing the surface as a side effect of its swelling with magma. And this time, it's an order of magnitude larger.
More details, plus pictures and videos, below the fold on today's edition of Eldfjallavakt!
Around 5 AM local time a second surface lava eruption commenced on Holuhraun. The new eruption is positioned to the north of the previous one and is larger. Its length is estimated at 1 to 1.5 kilometers long versus 600-1000 meters for the previous eruption. The southern end is about the same distance from the glacier, while the northern end stretches further north. The lava fountains are estimated at 60 meters high and most importantly the lava flow is estimated to be 50 times that of the previous eruption.
Instrument-only flight has once again been banned over the region up to 6000 feet due to the risk of the eruption accelerating to an explosive phase, although there are no signs of that at present. This time, the flight ban does not include Akureyri, which is good. It's not expected to have an impact on commercial aviation. There have been delays last night, but these were due to the remnants of Cristobal, who has been giving us a better storm than your typical post-hurricane does and made me have to rush out last night to build a windbreak around my plants..
Here's a video of the eruption, taken during a brief gap in sandstorms:
Update, 12:00 31 august:
Update, 12:20 31 august:
Here's some closeups of the lava from yesterday's eruption, before the new one began:
As for the significance of this latest eruption: it's magnitude at present appears to be faster than the rate of influx, so it could actually (unlike the previous eruption) let off a bit of pressure. However, most eruptions lose steam over time, so we'll have to see how it progresses. The rate of flow in this eruption is about 1000 cubic meters per second, the flow rate of a reasonably large river. There are no signs of a decline at this point in time.
The concerns at this point are whether it spreads, either south into the glacier where it could cause a flood, or northward toward Askja where it could risk interactions with that system. Really, an ideal situation would be a large lava eruption or series of large eruptions exactly in this location, no further south, and no further north, until the influx dies down.
This eruption is a direct consequence of the continual widening of the rift under Holuhraun. The dike has not been lengthening for several days, simply widening instead. The more the spreading in this location, the easier eruptions here become.
As mentioned in the article yesterday, we're also watching a lesser quake swarm under Herðubreiðartögl, east of Askja. This location was home to an earthquake swarm earlier this year; the fact that it has resumed suggests that this area is dealing with significant spreading forces as well. I have no information as to the significance of this on the area between the eruption/dike and Herðubreiðartögl. The "area between them" including Askja herself.
Update, 1:50 31 august: And here's my problem with making comparisons between this and the Krafla Fires in the 1970s/1980s. They're using the current eruption as a comparison with the Krafla Fires, pointing out that it's very similar to the largest eruption of the Krafla Fires. Which is all fine and good,except for the fact that it took a good chunk of a decade from the first lava eruption of the Krafla Fires to get up to its largest. This happened one day after the first lava eruption.
If one wants to compare to the Krafla Fires in terms of there being steady uplift, spreading, long-range dikes, lava flowing from fissure eruptions, etc, and take the Bárðarbunga caldera activity out of the picture and treat it as a totally separate event - fine, that's a fair comparison. But when you say that "it reminds me of the Krafla Fires", as some people have done, it leaves the public with the impression that the magnitude of the event is the same as the Krafla Fires. But nothing about what we've been seeing here - quake rate, quake magnitude, tremors, rate of uplift, rate of spreading, influx rate, and on and on - is of the same scale as the Krafla Fires, it's all far more powerful. In Krafla, the estimated influx rate of magma from the deep reservoirs was 5 cubic meters per second; here it's estimated on the order of 500. And this is a much more dangerous region.
That said, if we're lucky, perhaps the dike may yield just a "mega Krafla Fires" over the coming months, years, or more, not advance any more (even though the Krafla Fires were defined by regular dike intrusion), and take that element of the picture. But we still better hope that none of the activity in either Askja or Bárðarbunga that's been happening doesn't add some color to the scene.
Update, 14:30 31 august: I just realized that I haven't posted a webcam link in a while. So here you go. :) Again, be aware that there's bad weather right now.
Update, 19:00 31 august: The eruption, which has been described by people on the site as looking like a glowing dragon, continues unabated. Lava fountains are now reported up to 70 meters high. Here's a video from on-site:
You can see a time lapse from a distance here:
That said, I think this one below is the coolest yet :)
The widespread sandstorms have been causing many people to report in ash falls, although scientists say that they believe that it is just from the storm.
There was a 4.9 quake in Bárðarbunga a little bit ago. These things are just so dang commonplace now.
The magnitude the eruption is now said to be 50 times that of the former eruption, although it's not clear whether they're talking about flow rate or volume. The rate is said to be 3 times more than that of Eyjafjallajökull, although it's not clear whether they're talking about Eyjafjallajökull's lava component alone (aka the Móði and Magni eruptions on Fimmvörðuháls) or a total mass equivalent counting the ash from the primary eruption.
Update, 19:30 31 august: I'm seeing a fair bit of concern expressed by the team that this eruption may keep lengthening, which would be bad in both directions. We want it to remain precisely where it is right now ;)
Here's the best map I've seen of the situation yet, from Háskóli Íslands (University of Iceland):
And here's a progression of activity over time:
Each circle is a quake. How far up it is represents how far north it is, while how far it is to the right indicates how recent it was. So you can see the timing of the first eruption coiniding with the first "cork popped" event, and so forth.
Lastly, here's a series of pictures taken just briefly before the new eruption started up. One of the people at the scene joked that their rear ends would have gotten pretty hot if they'd taken too long ;)
The air traffic alert color has been lowered from red to orange.
Update, 21:00 31 august: Newest news: Quakes are down. The eruption is believed to be lengthening to the north, but investigators can't reach it due to the weather. The lava fountains are now reaching as high as 100 meters. By comparison, this - from ground to the top of the torch...
... is only 92 meters.
Update, 23:00 31 august: Eruption flows are now estimated at 400 cubic meters per second, although it sounds more like a reestimate rather than a decline (another report says only 250. There is reportedly less activity on the southern end but more on the northern end, so the eruption is sliding north.
Geologist Ármann Höskuldsson says that it should begin to decline soon and he would expect tomorrow to see the fissure eruption coalesced into one or two craters. The research plane TF-SIF will fly over the area tomorrow morning, which is of course a good thing!
More news when it comes.
Update, 08:40 31 august: Quick morning update: contrary to some predictions, the flow has not reduced overnight, and is still estimated at 300-400 cubic meters per second. It has already flowed several kilometers from the fissure.
6 quakes over magnitude 3 since I went to bed, 3 of them over mag 4, one is a 5.0. All in the caldera. Quakes continue to be down in the dike / Holuhraun, as the lava outflow rate seems to be matching the reported dike influx rate; why break rock when can just pour out onto the surface?
One in every five quakes overall now is in Herðubreiðartögl, east of Askja - a concerning development that's been growing for a few days. Since nobody is yet to report on this, I've sent an inquiry to Ágúst, the researcher whose magma source theory I presented a couple articles back. I'll report in once I hear back from him.
I've got some nice pretty pictures but I'll save them for the next article. :)