A multi-scale risk assessment for tephra fallout and airborne concentration from multiple Icelandic volcanoes – Part 1: Hazard assessment

摘要: Abstract. In order to assist the elaboration of proactive measures for management future volcanic eruptions in Iceland, we developed a new scenario-based approach assess hazard associated with tephra dispersal and sedimentation at various scales multiple sources. The target volcanoes are Hekla, Katla, Eyjafjallajokull Askja, selected either their high probabilities eruption and/or potential impact. By coupling tephrostratigraphic studies, probabilistic techniques modelling, comprehensive scenarios both short- long-lasting compiled maps ground deposition national scale air concentration European using TEPHRA2 FALL3D models, respectively. New algorithms identification realistic sets eruptive source parameters investigated, which generation probability density functions scenarios. Aggregation processes were accounted empirical models. Outcomes, i.e. conditioned occurrence an eruption, help assessment comparison levels different scales. For example, Askja has 5–10% blanketing easternmost half country accumulation least 1 kg m−2. At continental scale, Katla producing ash clouds concentrations 2 mg m−3 over UK, Scandinavia northern Europe mean arrival time 48–72 h persistence 6–18 h. companion paper, Scaini et al. (2014) present vulnerability Iceland traffic airborne which, combined outcomes constitute one first multi-scale risk sedimentation.