How can information systems help in volcanic risk management?
Résumé
Efficient volcanic risk management requires prevention, crisis management and recovery tools that enable users to assess risk during the rest period, to optimize response capabilities during the crisis and to help for recovery after a disaster. Within the MIAVITA project, we investigated how two types of information systems can help in volcanic risk management: (1) WebGIS, designed to enable users to visualize a very complex database of volcanic and geological hazard and risk maps and (2) scenario builder tools intended to assess the potential damages induced by a hypothesized adverse event. The concepts tested within this study were tested over the Mount Cameroun Area, taking advantage of a previously undertaken field survey and hazard mapping study (Thierry et al., 2006). WebGIS are intended to provide users not familiar to GIS tools with the possibility to visualize the content of a complex database. Key users requirements here relate to the need for a structured and flexible GIS-database, but also to the need to manage user's privileges differently according to their profile, the status of the volcano and the capabilities of the system to manage queries. Finally, different status for data is acknowledged, from data than can only be interpreted by experts (e.g. some complex remote sensing products) to data that can be disseminated to any users (e.g. a regulatory hazard map). The tool developed by KELL was based on open source resources. While the developed tool is able to provide users with enough flexibility to respond to the users' requirements, it is necessary to own expertise in WebGIS to manage such tools in the long term in local volcano observatory. Unlike the seismic risk for which the main obstacle to the development of scenario-tools is the complexity of the damage functions of the building to a peak ground acceleration, the volcanic risk scenarios face three specific challenges: (1) human and economic damage are not only related to the collapse of buildings, but to a large number of geological phenomena (lava, pyroclastic flows, landslides, lahars, etc ...) that can affect a multitude of exposed assets (people, building, agriculture, large regional functions...) (2) the many features of damage to integrate into a tool are also very heterogeneous and are poorly constrained by observations, (3) the tool should be able to take into account a multitude of successive or simultaneous events during the sequence of an eruption. The temporal dimension of the event is thus more complex than in the case of an earthquake scenario tool. Finally, such tool is only able to address direct damages and will hardly provide any useful information with respect to potential indirect damages such as for example diseases due to water supply disruptions. These investigations undertaken within the MIAVITA project suggest that information systems can provide authorities and users not familiar with GIS with useful information that can help assessing the risk, but also to prepare for potential future crisis.