The explosive eruptions of Chaitén in 2008, Eyjafjallajökull in 2010 and Grímsvötn and Puyehue-Cordón Caulle in 2011 have demonstrated how events of only moderate size and intensity can result in significant disruption and considerable economic impacts both locally and regionally. In particular the Eyjafjallajökull eruption in spring 2010 caused unprecedented disruption to aviation with extensive closures of European air space, while ash from Chile’s Puyehue-Cordón Caulle circumvented the globe disrupting air traffic in Australia and New Zealand. These events have highlighted the need for better understanding of conduit processes in explosive eruptions, the controls of magma fragmentation, particle population characteristics, plume dynamics, interaction between plume and atmosphere, and the near- and far-field dispersion and deposition of tephra. The potential of ground-based and remote sensing techniques for detecting and quantifying the atmospheric ash-loading by volcanic plumes was demonstrated by observations during these eruptions, although more precise calibration and refinement of the techniques is required.

In this session we seek to address all observational and modelling aspects of the explosive eruptions of Chaitén, Eyjafjallajökull, Grímsvötn and Puyehue-Cordón Caulle. This includes course of eruption events, magma chemistry and physics, magma fragmentation along with mechanisms that promote ash generation, tephra transport and dispersion, tephra sedimentation and physical properties, atmospheric interaction and dynamics of volcanic plumes in the near- to far-field, and methods of ash detection and quantification. A particular aim for this session is to bring together the traditionally separate communities of solid earth scientists (geophysicists, petrologists, physical volcanologists, etc.) and atmospheric scientists (meteorologists, atmospheric chemists and physicists, remote sensing scientists etc.).