Suchergebnisse

Abstract. The 6-month-long effusive eruption at the Fagradalsfjall volcano in 2021 is the most visited eruption site in Iceland to date (June 2023), and it needed intense lava flow hazard assessment. In this study we document how strategies for lava flow modeling were implemented using the stochastic model MrLavaLoba to evaluate hazards during this effusive event. Overall, the purposes were threefold: (a) pre-eruption simulations to investigate potential lava inundation of critical infrastructure, (b) syn-eruption simulations for short-term (2-week time frame) lava flow hazard assessment and (c) syn-eruption simulations for long-term (months to years) hazard assessments. Additionally, strategies for lava barrier testing were developed, and syn-eruption topographic models were incorporated into simulations in near real time. The model provided promising results that were shared regularly at stakeholder meetings with the monitoring personnel, scientists and civil-protection representatives helping to identify potential short-term and long-term lava hazards. This included evaluation of the timing of barrier overflow and the filling and spilling of lava from one valley to another. During the crisis the MrLavaLoba model was updated to increase functionality such as by considering multiple active vents. Following the eruption, the model was optimized substantially, decreasing the computational time required for the simulations and speeding up the delivery of final products.

The effusive six months long 2014-2015 Bárðarbunga eruption (31 August-27 February) was the largest in Iceland for more than 200 years, producing 1.6 ± 0.3 km3 of lava. The total SO2 emission was 11 ± 5 Mt, more than the amount emitted from Europe in 2011. The ground level concentration of SO2 exceeded the 350 µg m−3 hourly average health limit over much of Iceland for days to weeks. Anomalously high SO2 concentrations were also measured at several locations in Europe in September. The lowest pH of fresh snowmelt at the eruption site was 3.3, and 3.2 in precipitation 105 km away from the source. Elevated dissolved H2SO4, HCl, HF, and metal concentrations were measured in snow and precipitation. Environmental pressures from the eruption and impacts on populated areas were reduced by its remoteness, timing, and the weather. The anticipated primary environmental pressure is on the surface waters, soils, and vegetation of Iceland. ; Funding for the research came from the Icelandic government via the Icelandic Civil Protection Agency, the EC FP7 Framework programme via the Futurevolc project, the Swedish Research Council FORMAS supported the DOAS measurements Geochemical Perspectives Letters Letter Letter Geochemical Perspectives Letters 92 Geochem. Persp. Let. (2015) 1, 84-93 | doi:10.7185/geochemlet.1509 Geochem. Persp. Let. (2015) 1, 84-93 | doi:10.7185/geochemlet.1509 93 and The French centre of excellence "Clervolc" programme financed the microprobe analysis. We are grateful to the Environmental Protection Agency in Ireland, the National Institute for Public Health and the Environment in the Netherlands, the Belgian Interregional Environment Agency, the Department for Environment Food & Rural Affairs in UK, and the Environment Agency of Austria for ground–level SO2 concentration data in air in the respective countries. ; Peer Reviewed