Volcano Briefing: Up To Thirty Meters Of Lava Under The Crust

An earthquake with a magnitude of 3.5 occurred on September 5 just north of the crater in Meradalir, reports RÚV.

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No embers have been seen in the crater for over two weeks. Despite that, about a thousand people have visited the eruption site in the last few days. Scientists believe it could take two to ten years for the lava to solidify fully. While it is thickest around the crater, it is still hot up to thirty meters below. A little over a week after the Meradalir volcanic eruption, the magma came from a greater depth than the first few days, according to the results of the Institute of Earth Sciences.

Apart from the recent earthquake, everything has been fairly quiet in Meradalir for over two weeks. Natural disaster experts at the Icelandic Met Office believe that it is likely that the eruption channel has become blocked, although it is still too early to declare the eruption closed.

Experts from the Institute of Earth Sciences have recently been looking over igneous and lava samples that were collected during the eruption in Meradalir. The results show that there is little difference in their chemical composition between years, and the lithological appearance of the samples is also similar.

In the first few days, magma emerged which had probably been lying in the eruption channel for a whole year or since the last eruption, according to Þorvaldur Þórðarson, professor of volcanology. “It is by far the simplest to think of it as a pipe. There is something in the pipe, it extends from some depth and is relatively shallow, let’s say only three to four kilometeres deep. The magma that wants to come to the surface and initiates the eruption, this deep-seated magma, has to push all of this out first,” says Þorvaldar.

Representatives of the Institute of Earth Sciences have not been able to fly over and measure the lava since mid-August, or about a week before the eruption stopped. By then, the lava had reached a maximum thickness of 30 meters, where it is thickest around the crater, but scientists believe that little has been added since then.

The total volume of volcanic material was 12 million cubic meters, or about eight percent of what came up in Fagradalsfjall last year. The average lava flow was seven cubic meters per second, or slightly lower than the average for the 2021 eruption, according to measurements by the Institute of Earth Sciences.

The magma was up to 1200 degrees centigrade throughout the eruption, which is similar to the eruption of 2021. The police chief in Suðurnes sent out an announcement last week to emphasise that although no embers can be seen in the crater, the lava is still dangerously hot and it is forbidden to go onto it.