August 13, 2021

Two days into August: The eruption is still with us

The eruption in Geldingadalir adjacent to Mt Fagradalsfjall develops as time flies. Currently, periods with a lively eruption, with some magma fountain activity, have alternated with periods where no action is visible in the crater.

The eruption in Geldingadalir adjacent to Mt Fagradalsfjall develops as time flies. Currently, periods with a lively eruption, with some magma fountain activity, have alternated with periods where no action is visible in the crater. The average lava discharge figure varies between 7 and 11 cubic metres per second. The lava does flow in rivulets on the surface of the new lava mass but to a large extent also in a plumbing system below the surface. The flow area is 4,3 square km but the lava cover is very thick in places, making up a total mass of 110 million cubic metres.

If the eruption continues for months or even years, a lava shield might slowly be built out of countless lava layers. The effusive eruption has entered successive phases as follows:

  1. A short lava eruption commences from a new volcano-tectonic fissure with one main crater.
  2. Up to eight craters are active on the fissure, following an opening farther to the northeast.
  3. One of the new craters develops into the high, main vent – high magma fountains and increased lava discharge.
  4. Periodic visible activity follows with lessening fountain activity – somewhat decreased but stable lava discharge.

The 5. phase would include a bubbling, rather quiet lava pond in a top crater of a growing lava shield and lava flowing in a complex system of runnels and lava tubes.

Tourism benefits from the eruption. With rather strict border regulations, Iceland now copes with a growing number of visitors. Thousands of them hike every week to marvel the crater activity and lava flows. Icelanders have flocked to the eruption site as well. A total of over 200,000 people have visited the vantage view points since March 19th.


(Photo: Ragnar Th. Sigurdsson)