Volume, Discharge Rate and Lava Transport at the Fagradalsfjall Eruption 2021: Results from Near-Real Time Photogrammetric Monitoring
Abstract
The ongoing effusive eruption at Fagradalsfjall on the Reykjanes Peninsula, Iceland, began on March 19, 2021.To monitor key eruption parameters (i.e. effusion rate and volume), near-real time stereo-photogrammetric monitoring is performed using a combination of satellite and airborne stereo images. This monitoring started ~11 hours after the eruption began. On July 27, 2021, 30 surveys had been performed providing an unprecedented temporal data set (including volume and discharge rate estimates, orthophotos, thickness maps and thickness change maps) delivering information and maps necessary for evaluating hazards. Currently, the lava-flow field covers 4.3 km2 and the estimated bulk (including vesicles and macroscale porosity) volume is 109 million m3, giving an average discharge rate (from the start of the eruption) of 9 m3/s. In phase 1, the time average discharge rate (TADR) slowly but steadily declined, ranging from 3.87.4 m3/s with a mean value of 5.7 m3/s. Similarly, the TADR ranged from 4.6 to 7.8 m3/s, with a mean of 6.2 m3/s in phase 2. In phase 3, the TADR increased from 7.5 to a maximum of 13 m3/s with a mean of 9.3 m3/s. Compared to recent Icelandic eruptions, the evolution of the discharge rate of Fagradalsfjall is very unusual, having a low, fairly stable discharge in phases 12 and increasing in phase 3. We speculate that the eruption at Fagradalsfjall may therefore not be controlled by a pressurized magma chamber, unlike recent eruptions in e.g., Krafla, Hekla, Grimsvotn and Bararbunga.
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2021
- Bibcode:
- 2021AGUFM.V35F..01P