Volume, effusion rate, and lava transport during the 2021 Fagradalsfjall eruption: Results from near real-time photogrammetric monitoring

Abstract

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The Eruption in Fagradalsfjall (2021, Iceland): How The Operational Monitoring and The Volcanic Hazard Assessment Contributed to Its Safe Access

“…The eruption at Fagradalsfjall emitted a total amount of SO 2 on the order of 0.3-0.9 Mt (Pfeffer et al, in preparation) and a total bulk volume of lava of 150 ± 3 × 10 6 m 3 (Pedersen et al, 2021). Although the 150 million m 3 bulk volume makes this eruption of average size for Iceland (Gudmundsson et al, 2008), it was small compared with the most recent basaltic eruption in Iceland, within the Bárðarbunga volcanic system in 2014-2015, when 9.2 Mt of SO 2 was released and 1.4 km 3 of lava was extruded (Pedersen et al, 2017;Pfeffer et al, 2018) during a similarly 6-month long eruptive period.…”

“…Through regular aerial monitoring surveys and photogrammetry, it was possible to keep track of the lava eld evolution and to assess the extrusion rate. The last survey con rmed that a total of 150 ± 3 × 10 6 m 3 bulk volume of lava had been extruded over a six-month period and the lava eld emplaced covers an area of 4.8 km 2 (Pedersen et al, 2021). Lava ows were issued from all ssures/openings, so that the lava propagated both toward the NE (Meradalir valley after 5 April) and towards the SE (Syðri-Meradalur valley after 14 April) after ponding for the rst four weeks in the Geldingadalir valley.…”

“…Since the beginning of the eruption, photogrammetry of the lava eld was acquired by aircraft. This information has been vital for assessing the lava effusion rates, extent and emplacement style (Pedersen et al, 2021), as well as to initialize the lava ow simulations to anticipate the possible further evolution of lava inundation.…”

“…During the initial phase, the eruption progressed with a fairly stable extrusion rate, on average 4.9 m 3 /s lava (Pedersen et al, 2021), and 25-59 kg/s SO 2 (Pfeffer et al, in preparation). Seismicity was still elevated during this period and about one thousand earthquakes > M1 (manually checked) were detected in the vicinity of the eruption site during the rst two weeks.…”

Unravelling the Deformation of Paleoproterozoic Marbles and Zn-Pb Ore Bodies by Combining 3D-Photogeology and Hyperspectral Data (Black Angel Mine, Central West Greenland)

“…Today, digital photogrammetry is an efficient and powerful geological tool used for geological problem solving [24] within the geoscientific community. Examples are plentiful and range several orders of scale, including detailed close-up investigation of ice surfaces [25], to near real-time volcanic eruption monitoring [26] and regional geological map making [13,27,28].…”