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The longest eruption this century

17.09.2021 - 10:36
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 Mynd: RÚV
The volcanic eruption on the Reykjanes peninsula yesterday became the longest eruption in Iceland so far this century, overtaking Holuhraun for length of eruption—though not yet coming close when it comes to size.

According to a social media post from the South Iceland volcano and natural hazards group, being the longest Icelandic eruption of the 21st century so far is worthy of note, but is but the blink of an eye in a geological time frame.

According to the latest readings, the Geldingadalir lava field is now 4.6 square kilometres in area and contains 142 million cubic metres of lava. By comparison, the Holuhraun lava field from the 2014-15 eruption covers an area of 85 square kilometres.

The lava flow rate at Fagradalsfjall has fluctuated somewhat over the months, reducing dramatically in July, and rising again to around 8.5 cubic metres per second today. 

“181 days have today passed since the eruption started on 19th March. Therefore, the eruption has become longer-lived than the eruption at Holuhraun, which lasted 180 days. The eruption there started on 31st August 2014 and ended on 27th February 2015. The ‘Surtsey Fires’ are generally thought to be the longest-lived eruption in Icelandic history. The eruption there lasted, with pauses, from November 1963 until June 1967,” the social media post explains. 

Scientists say it is impossible to say when the eruption might end. One such scientist is the geophysicist Páll Einarsson: “It is nearly pointless to say anything about that and really nothing that we are measuring that indicates the eruption is either ending, or that it will continue. There is nothing that can tell us about that. The current resurgence of the eruption now is a good lesson in that. Because there was a pause for nine days and many had decided that was enough to say that the eruption was now over. But that is not the case and it started again wit the same power as before,” Páll told RÚV this weekend. 

Páll says scientist have learnt an incredible amount from the Reykjanes eruption and are sweating over computer keyboards writing articles about all the things they have learnt, and are still learning. 

“This is the first eruption we have seen on this branch of the Reykjanes plate divide. It is valuable for this reason alone. But there is also the fact that this eruption is in the most unlikely position on the entire Reykjanes peninsula for an eruption. A year ago, we would probably never have guessed this would be the next eruption site. It is between the most active volcanic systems in the area. Between Reykjanes and Svartsengi on the one hand, and on the other, Krýsuvík. Those systems are much more active when looking at the longer term. This teaches us that unlikely events happen sometimes,” Páll says. 

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