Modelo de multi-amenaza natural para países en vías de desarrollo: caso de aplicación cantón de Poás, Costa Rica

For the Natural Hazards assessment it is recommended to use a probabilistic approach, but most of the time this involves a long record of quality data. This way, there are some frameworks for multi-risks analysis in order to integrate properly the risks on multi-hazards spaces; for example, the Bayesian logic tree. However, that condition is rarely occurs in less developed countries, where the historical record is short and instrumental data is scarce. Therefore, we have developed a heuristic approach that allows us to combine individual qualitative assessments to multi-hazards spaces in order to guide the land by using the planning and local risk reduction strategy. The Costa Rican law is demanding the local governments to use the Environment Fragility Index (IFA by its acronym in English) however; its method has misconceptions and algorithm errors, the resulting in an inappropriate assessment on multi-hazards spaces. For this reason, we present a framework analysis multi-hazard, which include the spatial interactions from the individual hazards that are presents in the same space, considering possible interactions between hazards that spatially match using an interactions matrix and the relative frequency of the events. In addition, this model can be tuned up in order to apply it in other countries. In order to apply this model, we chose the Poás Township, Costa Rica, where there are volcanic hazards (tephra fallout, acid rain, lahars, etc) hydrological hazards (fast floods, landslide) and seismic hazard. The result of the model in Poas lets us to identify the distribution of the hazard, in general terms; the north part is the most hazardous, the center is moderate and the south part is the least hazardous