Remote sensing and GIS for natural hazards assessment and disaster risk management

The world has experienced an increasing impact of disasters in the past decades. Many regions are exposed to natural hazards, each with unique characteristics. The main causes for this increase can be attributed to a higher frequency of extreme hydro-meteorological events, most probably related to climate change and an increase in a vulnerable population. To reduce disaster losses, more efforts should be applied toward disaster-risk management, with a focus on hazard assessment, elements-at-risk mapping, and vulnerability and risk assessment, all of which have an important spatial component. Multi-hazard assessment involves the assessment of relationships between different hazards, especially concatenated or cascading hazards. The use of Earth observation (EO) products and geographic information systems (GIS) has become an integrated approach in disaster-risk management. Hazard and risk assessments are carried out at multiple scales, ranging from global to community levels. These levels have their own objectives and spatial data requirements for hazard inventories, environmental data, triggering or causal factors, and elements-at-risk. This chapter provides an overview of various forms of spatial data, and examines the approaches used for hazard and risk assessment. Specifically, hazard examples include earthquakes, windstorms, drought, floods, volcanic eruptions, landslides, and forest fires. Several approaches are also treated that have been developed to generate elements-at-risk databases with emphasis on population and building information, as these are the most used categories for loss estimation. Furthermore, vulnerability approaches are discussed, with emphasis on the methods used to define physical vulnerability of buildings and population, and indicator-based approaches used for a holistic approach, also incorporating social, economic, and environmental vulnerability, and capacity. Finally, multi-hazard risk approaches and spatial-risk visualization are addressed. Multi-hazard risk assessment is a complicated procedure, which requires spatial data on many different aspects and a multi-disciplinary approach. Within this procedure, geographers and in particular geomorphologists can play a key role, as they are able to integrate spatial information from various disciplines. The research challenge for geomorphologists is to focus on the integrated modeling of multi-hazards that share the same triggering event or occur as cascading hazards.