Long eruption is now expected in Fagradalsfjall in Geldingadalir valley (soon a former valley) based on lava chemical details

This is not a update on the eruption. There has not been any major change in the eruption at the writing of this article.

University of Iceland has released a report that can be read here (pdf) showing that the magma that is now erupting comes from the depth of 17 to 20 km. Crust at this location on the Reykjanes peninsula is around 17 km deep. A 3D map can be found here of the eruption. I think it is going to updated regularly by ÍSOR. The lava that is now erupting is part of Tholeiitic magma (Wikipedia). The lava is 1180C when it erupts from the ground.

What seems to be now happening is that a shield volcano is forming. It is a question if this is going to result in a formation of new magma chambers along the dyke where it formed. There is continued risk that new vents and fissures eruptions opens in this change can happen without warning. Based on earthquake activity it seems that the dyke continues to be active rather than having turned into rock by cooling.

The eruption is also high in the following gases, CO (Carbon monoxide), CO2 (Carbon dioxide), SO2 (Sulfur dioxide) and other dangerous gases.

It is now estimated that the Geldingadalir valley is going to overflow in 8 to 18 days and currently a lava pond is forming at this location. Once that happens the lava is going to flow into nearby valley (I can’t find the name of it). One of the valley the lava is in the end going to flow into Nátthagi valley if the eruption lasts long enough.


3 Replies to “Long eruption is now expected in Fagradalsfjall in Geldingadalir valley (soon a former valley) based on lava chemical details”

  1. This seems very similar to the 2018 eruption of Kilauea. My guess is that this eruption lasts for weeks to months, with a pause of maybe about 1-2 years before resuming magma pressure (this seems to be the rate of the new intrusion anyhow) to the point of a new eruption, but the 1983-2018 eruption of Pu’u’o’o crater at Kilauea was the result of a well-established magma channel. Shield volcanism is reliant on several layers of magma chambers, and rock fractures. The eruption only ended when the main magma chamber emptied to the point that it was no longer providing a source downrift. After the rift closed, inflation resumed, and lava again erupted at the summit (after having presumably closed off the rift system). If this is a simple dyke eruption, we would expect it to already have ceased. My guess is that the magma dyke may have been sourced from the mantle and not from Krysuvik. If that’s true, this could be a long-lived monogenetic eruption much like the eruption of Paricutin in Mexico. I am still skeptical of the shield volcano theory, but really it’s all still wait-and-see. Given the temperature of the lava, it’s difficult to imagine this not being at least a several month long eruption, if not more. How exciting it is anyway!

  2. We all know that we are guessing. Experts and amateur’s alike. But since the lave has its origin from the big mama all things points to a long duration of this transforming event. But all Iceland is transformation. Not like Scandinavia with its safe rock.

  3. Because of website traffic I am going to move this website to a new server maybe in April. But it might get delayed until June depending on when I can afford the move. This is not a fully dedicated server. I think this is more of a VPS setup but fully managed. There where some problems during the usage spike before the eruption on the Reykjanes peninsula. This is tiny bit more expensive than the shared hosting it currently is on but I only have to move this website. Other websites that I have are going to stay on shared hosting because they don’t get any traffic of any amount anyway.

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