Plain Summary
On March 19, 2021, an eruption began at Mt. Fagradalsfjall after 781-years dormancy on the Reykjanes Peninsula, Iceland. To monitor and evaluate hazards of the eruption, satellite and airborne stereoimages were processed and made publicly available on the same day as they were surveyed. The data were used to create 3D models of the lava and update the lava volume and growth rate. The resulting maps were used by disaster response teams to evaluate the risk of the lava flow to nearby infrastructure and to manage tourism in the vicinity of the eruption. On September 30, 2021, the new lava flow-field covered 4.8 km2, was up to 124 m thick and had a mean thickness of 30 m, yielding a total bulk volume of 150 million m3. The mean discharge during the six months of the eruption was 9.5 m3/s, equivalent to filling one Olympic swimming pool every four minutes.