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.
Low-frequency seismic chart by the MET Office. Graph: Icelandic MET Office
This is evident from low-frequency seismic monitoring by the Met. Office (the blue line in the graph). The lava discharge, however, has lessened somewhat. The average figure is 6-7 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. 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:
Fagrahraunseldar eruption. Picture taken on 12 July 2021 by Ragnar Th.
