Lahars in Ecuadorian volcanoes: overview of the hazards and monitoring strategies

Lahars are dense and viscous gravitational flows, composed by a mixture of water and suspended rocky materials, generated in volcanic edifices. Ecuador contains an environment where the main ingredients for the generation of lahars are abundant: active volcanoes, tropical rainy seasons and glaciers interact with each other to shape both the geological and societal landscape of the country. Tungurahua and Cotopaxi volcanoes represent end-members where hazards associated to lahars can be studied in dramatically different time- and space-scales. However, regardless their scale, the strategy to monitor and identify the occurrence of these flows is currently based on seismic instruments and is directly linked to an early-warning system. The innovative approach to calibrate the monitoring network in order to obtain real-time quantitative information about lahars will be presented.