It's now clear that the Holuhraun eruption is the greatest eruption in Iceland in more than 230 years. This eruption some unique qualities when compared to other Icelandic eruptions through the ages - but also on a global scale.
Earlier this week scientists announced with certainty that the new still-growing lava field north of the Vatnajökull glacier, whom many want to be called Nornahraun (Witches's lavafield) is larger than any other lava field since the Laki eruption in 1783-1784 - an eruption that had greater and more dire consequences than most other eruptions in recorded history.
The lava field now covers 65 square kilometers and is still growing rapidly.
FIVE ERUPTIONS IN THE AREA
Volcanologist Ármann Höskuldsson says that the eruption has kept a steady flow since Oct. 6th and that it is impossible to predict when it will stop. As has been stated before it is considered a given that another eruption will soon begin in the area, considering the constant activity in the area. It is now accepted that five eruptions have taken place in the area; two sub-glacial ones, two smaller eruptions north of Dyngjujökull and then the one that's currently in action.
"Although the lava flow has reduced somewhat, it's still over 100 square meters per second, which equals the Skjálfandi river during summer time. The flow was immense in the beginning and was triple its current volume," states Ármann and adds that the lava flow covered 20 square meters of land per second.
Ármann agrees that the eruption is of a historic scale, and adds that it made the history books in the first couple of weeks. "People tend to measure volcanic eruptions by the cubic meter volume that emerges from the volcano, but that's not a good scale of measurement. It's more about the speed of things. You can talk about big volume volcanoes that took decades or even centuries to accumulate. In this case we're getting an incredible amount in an almost absurdly short amount of time.
In terms of volume Holuhraun beat Fimmvörðuháls before noon on the first day, but the Fimmvörðuháls eruption lasted for two weeks. During the first week we realized that the Holuhraun eruption was something we'd never dealt with before." Ármann believes that the total volume of the lava field is now around a million cubic kilometers, but the Hekla eruption in 1947, which is often used as a comparison for large eruptions in Iceland, had a much lesser lava field volume. "It's surpassed everything that we know of."
GAS REMAINS A RISK
The gas pollution from the caldera is currently the biggest concern, but in the beginning the force of the eruption and the thermal uptake was so great that the gas was launched high into the sky where no one noticed it. Later, as the force of the eruption diminished, the gas has lain over the land and been a nuisance.
There's no end in sight to this problem, in fact experts like Þorsteinn Jóhannsson at the Icelandic Environmental Agency are predicting the exact opposite - that the winter weather will escalate the problem, especially during the calm frost. "This problem will only get worse with time and it is unlikely that the eruption will grow in force and start kicking the gas to a higher altitude."
ICELAND AND THE WORLD
Even when the Holuhraun eruption is compared to eruptions all over the world the facts remain the same. Ármann states "We'd have to go way back, there's a huge eruption in the Canary Islands during the middle of the 18th century that's probably larger than this one. So even on a global scale the Holuhraun eruption is making history. Simply put it's the biggest lava eruption Mankind has seen since the 18th century."
When asked further about the eruption, Ármann notes that the eruption has already lasted longer than both the Fimmvörðuháls and Eyjafjallajökull eruptions combined. Ármann also adds that the magma that's coming up is unusually hot; it's around 1200 C° which is around 200 C° greater than magma coming from other known eruptions.
"These facts support the theory that this is a tear from the fireheart itself, the hotspot under the country. This is coming straight from the mantle and up to the surface. This makes it very difficult to predict when the eruption will end.
But that's not all. Ármann mentions that Icelandic geologists have poured over every text and historic reference they know of, looking for examples of a series of events anything like that which the nation has been seeing in Bárðarbunga for the past couple of months.
"Bárðarbunga is a huge concern and we've never seen anything like this. The large amount of strong earthquakes, sometimes many a day, for days and weeks on end.
We've looked up every observed volcano, and this is unprecedented. That makes the big picture much harder to see, because we don't know what it all means," says Ármann who adds that the data that has been collected from the Holuhraun eruption will take several years to work through. No one can claim when that data gathering will end though, as the Holuhraun eruption is surely only the beginning of a far longer series of events in and around the Vatnajökull glacier.