Losses arising from extreme natural hazards are increasing worldwide, and are expected to continue to do so, often as a result of the increased exposure and vulnerability of human society. Recent disasters, especially extreme seismic events, have clearly emphasized the importance of the analysis and understanding of concatenated hazard events. There is also an increasing realization that a “multi-hazard and risk” framework is necessary if one is to effectively assess the consequences of natural and anthropogenic disasters, and to optimize the available resources for mitigating against such events.

The aim of this session is to discuss new approaches in extreme- and multi-event hazard and risk assessment, with an emphasis on seismic hazard. The intention is to consider a number of questions and issues, including issues and challenges in hazard (single-, multi- and extreme-) assessment and mitigation; how the modelling of extreme events can contribute to hazard studies? the integration of hazards and risks into common frameworks; which hazard maps do policy makers and the society need and what can scientists and researchers provide? what elements are still still missing from hazard assessment? how can risk from extreme events be compared to that from smaller, but more frequent, events? theoretical issues and development of tools for assessment and validation of hazard models; discussion of basic and new requirements for operational hazard assessment; lessons learnt from recent disasters and their application to models' revision and improvement; and the development of cost-effective mitigation strategies. Case studies, where multi-hazard, risk and extreme events are considered, are of interest.