On March 19th, 2021, after weeks of multiple earthquakes on Reykjanes peninsular eruption began in Geldingadalir, between Mt. Fagradalsfjall og Mt. Keilir. At first it was thought to be from recent dike intrusion of magma that has formed under the peninsula over a few weeks. First news of the eruption came from locals that noticed some visible glow just before 21:00 that evening. The eruption was small and slow running lava did not cause any panic and there for no concern over property damage. The international airport in Keflavik was not affected as the no-fly zones over the eruption did not include Keflavik.
For next day’s little changes were in the eruption; steady lava flow slowly filled the valley and little danger for endless visitors to the site.
On March 24th scientist provided remarkably interesting result of their analyzes of the lava, as they thought it came directly from the mantle source 15-20 km depth. So the idea of the lava coming from shallower reservoirs could not be true as the composition was primitive, without chemical alteration that would have occur in less depth. The lava effusion rate was estimated to be around 5-10 cubic meters per second for the first week.
This eruption was the first for over 800 years in Reykjanes peninsular and such similar magma eruption was last thought to have erupted 14.000 years ago on Reykjanes. According to geologist Magnus A. Sigurgeirsson quoted in a press article, this eruption could last a long time, even years.
Enjoy this clip from www.mbl.is from March 20th 2021.
and these pictures.