An integrated, replicable Landslide Early Warning System for informal settlements – case study in Medellín, Colombia

Abstract. Due to climate change and growing urbanization, fatalities from landslides are rising worldwide, and thus solutions for people at risk are needed. This is especially the case for the Andean cities which are often expanding into the steep slopes surrounding them. In Medellín, Colombia, a combination of landslide-prone dunite rock and steep slopes in the east of the city creates a high-hazard scenario for about 87,000 residents, most of whom live in informal settlements. We developed a landslide early warning system (LEWS) which can be applied in such semi-urban situations. The LEWS consists mainly of a measurement system of horizontal and vertical sensor lines across the slope and autonomous point-sensors in between these lines. All parts of the LEWS, from hazard assessment to the monitoring system and the reaction capacity, are supported by extensive activities together with the local community to gain trust and create synergies. This also includes local authorities, agencies and NGO's. To test such a system, a prototype has been installed in a neighborhood in Medellín in 2020–2022. The experiences of this installation resulted in a framework for LEWS's of this kind which we have compiled on a wiki-page to facilitate replication by people in other parts of the world. Hopefully, this can stimulate a lively exchange between researchers and other stakeholders who want to use, modify and replicate our system.