Curtains of fire happen when an underground “magma tunnel,” as it’s known in Icelandic (English speakers say “dike”), breaks through the ground.
Magmatic gases blow off, producing the fountains; vents soon consolidate into just a few active centers; and incandescent lava streams out into the countryside.
Lava fountains in a row are called “fire curtains” for obvious reasons:
As a Kindle Vella chapter, this was a text link, not a live video, which is why I describe it afterwards — here, let’s take advantage of the blog tools and watch it!
That video shows the webcam view of a fire curtain opening up on December 18, 2023, a little after 10 p.m., in southwest Iceland, about two miles north of the port town of Grindavik.
First there is a big burst of orange light and the camera zooms in on some very impressive lava fountains, hundreds of feet tall.
Then more and more fissures open up on either side of the first vent and start fountaining, too.
Overall, at its longest this fire curtain contained five active vents and it extended for about 2.5 miles (4 kilometers) across the land.
The eruption didn’t last very long. Fountaining activity was down to three vents the next day, then two on the 20th, and it was all over by the morning of December 21.
No one was hurt.
Scientists, officials, and emergency personnel had seen this coming, although they could not be sure of the exact location, and they had posted warnings for months beforehand (which is why the webcam was out there in the first place).
Another big clue of impending eruption: the powerful earthquakes on November 10 and 11 that marked the underground opening of this dike as it branched off from a somewhat deeper body of magma that experts first detected in 2020, sitting about 3 miles (5 km) below the nearby Svartsengi Plain.
Those quakes caused major structural damage, since the new dike went right underneath Grindavik and on out to sea, and so the town was evacuated long before the night sky to the north suddenly turned orange on December 18.
Fortunately, the lava flowed east, and residents will not have to cope with lava damage from this eruption if and when they return.
But there will be more eruptions, more fire curtains. Grindavik sits in a part of Iceland — the Reykjanes Peninsula — that just woke up from an 800-year sleep.
The region last erupted in the 1200s. During the long quiet spell after that, many people moved in and settled down.
Then came the Geldingadalir eruption in 2021, then the Meradalir eruption in 2023, a brief one at Litli-Hrutur in early 2023 — and now this short eruption near Grindavik.
The geologic record shows that this is how the Reykjanes Peninsula operates: off and on, generally small in volume, and over many decades or longer until it finally settles back into another 800- to 1,000-year nap.
This is what the descendants of all those people who moved in during more peaceful times have to look forward to.
Hazard — but also benefits
Dealing with volcanic threat is hard, but Icelanders know that the volcanoes also provide benefits.
In fact, their island nation only exists because of volcanism.
It’s part of the Mid-Atlantic Ridge — a spreading center where new basalt oozes out of the planet and turns into hard rocky tectonic plates that trundle off on either side of the ridge — westward for the North American plate and eastward for Eurasia — as the Atlantic Ocean continues to widen at a rate about as fast as our fingernails grow.
There are a couple of places in Iceland where you can actually stand in between the North American and Eurasian plates, but for the area we’re looking at in this episode, the plate boundary is underground and passes across the middle of the Svartsengi Plain.
Ordinarily, mid-ocean ridges are hidden by deep water. At Iceland, though, the ridge has been brought up above sea level by a mantle plume — a “hotspot” — that also contributes to Iceland volcanism.
The plume is centered east of the Reykjanes Peninsula — near Bardabunga Volcano (which produced a huge curtain of fire and flow field in 2014 and early 2015; this video was taken of the lava fountains about three hours after that eruption began:
What this strange combination of spreading ridge and hotspot means for Firelanders Icelanders is this;
- A wealth of geothermal energy resources. For example, the geothermal power plant at Svartsengi supplies electricity, heat, and drinking water to more than thirty thousand people!
- A spectacular landscape that makes Iceland one of the world’s top travel destinations.
- Lots and lots of eruptions and volcanic hazards — glacial outburst floods, pyroclastic flows, ash plumes and fallout, earthquakes, poisonous gases, lava flows, landslides, and volcanic lightning. In a word, trouble.
Not every hazard maxes out at each volcano, of course.
In the Svartsengi area, lava is the main concern, though earthquakes, volcanic gases, and some small amounts of tephra (airborne volcanic debris) from a offshore eruption are possible, too.
Lava flows here aren’t speedy. People can get out of their way and, with care, can avoid being surrounded by a flow.
Lava is more of a threat to property and infrastructure (which is why they built a barrier around the Svartsengi power plant and nearby Blue Lagoon tourist venue, and why they are now constructing a barrier around Grindavik).
At this particular volcanic zone — which, again, experts say could remain active, off and on, for decades or even centuries — lava could also cut highways to most of Iceland’s international airport.
In due time, those roads will probably get barrier protection, too. Icelanders have been pacing themselves — putting up the labor-intensive and expensive barrier around the power plant when volcanic threat was generalized in location (under the plain) and now doing the same at Grindavik, since the area that recently hosted fire curtains is the most likely site of the next eruption.
It’s not a wasted effort. Chances are that these walls will be needed in coming months, years, or decades.
The boffins are hard at work, too, studying all the data this recent activity has given them, trying to better understand the regions magmatic “plumbing” in hopes of improving eruption forecasting accuracy and timing.
It is a very tough challenge, but one that Icelanders are up to handling.
As for the rest of us, some of the newly awakened Peninsula eruptions might be in remote areas where, as in 2021 to early 2023, it will be safe for tourists to visit and to stand in awe as fire curtains dance and play.
Monitoring:
Icelandic Meteorological Office.
More information:
Catalogue of Icelandic Volcanoes.
Global Volcanism Program. 2023.
Iceland volcanoes.
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NOTE: Today’s post was the first Vella chapter, published for January 7th and so before the 2024 eruptions. It’s dated, but you can check current information about the ongoing Reykjanes Peninsula fires at the top of the blog’s home page or click here.
Sources include:
Caracciolo, A.; Bali, E.; Halldórsson, S. A.; Guðfinnsson, G. H.; and others. 2023. Magma plumbing architectures and timescales of magmatic processes during historical magmatism on the Reykjanes Peninsula, Iceland. Earth and Planetary Science Letters, 621: 118378.
Grönvald, M., and Halldórsson, S. 2023. Undermining the prevailing theories about the Reykjanes Peninsula (via Google Translate. https://www.mbl.is/frettir/innlent/2023/12/21/grefur_undan_rikjandi_kenningum_um_reykjanesskaga/ (Icelandic)
Icelandic Meteorological Office. n.d. Bardarbunga and Holuhraun pages. https://en.vedur.is/earthquakes-and-volcanism/articles/nr/2947
___. 2023. Volcanic hazards. https://en.vedur.is/volcanoes/volcanic-hazards/
Karson, J. A. 2017. The Iceland plate boundary zone: Propagating rifts, migrating transforms, and rift‐parallel strike‐slip faults. Geochemistry, Geophysics, Geosystems, 18(11): 4043-4054.
Oregon State University. 2023. Volcano World: Curtain of Fire.
https://www.usgs.gov/observatories/calvo/news/fall-a-burning-curtain-fire-fissure-eruptions
Reynolds, P.; Brown, R. J.; Thordarson, T.; and Llewellin, E. W. 2016. The architecture and shallow conduits of Laki-type pyroclastic cones: insights into a basaltic fissure eruption. Bulletin of Volcanology, 78: 1-18.
US Geological Survey. 2023. Fall into a burning (curtain) of fire with fissure eruptions.
https://volcano.oregonstate.edu/definitions/curtain-fire
Flight To Wonder 