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

No abstract

No abstract

No abstract

The rapid estimation of expected impacts in case of an earthquake is extremely important for emergency managers and first responders. Current near-real-time damage assessment methods rely on ground-motion estimates and exposure or fragility datasets, in some cases integrating the shaking recorded at the site (e.g., from strong-motion monitoring networks). We propose a method that estimates the expected damages on buildings based on strong-motion recordings of a seismic event. The damage assessment is based on the maximum drift (interstory) or the displacement, which is estimated by considering in a first approximation the behavior of a specific building typology as a single-degree-of-freedom oscillator. The oscillator is characterized based on the analysis of the building stock and a large number of ambient vibration measurements performed in buildings. A specific damage state occurs when the interstory drift or displacement limits available in the literature for the specific building typology are exceeded. The method, here applied to a case study in northeastern Italy, can be applied to other seismic areas worldwide to provide quick, first-level estimates of expected damages.