Reducing spatio-temporal bias in the Cares landslide inventory (Picos de Europa National Park, Northern Spain)

The Cares route (Picos de Europa National Park - Northern Spain) is a hiking trail subject to intense tourist pressure, where visitors are frequently exposed to landslides, with rockfalls being the most common events. Despite the high frequency of these processes, no systematic inventory had been compiled to date. Since 2024, the SAFETRACK Project has been developing a comprehensive inventory of landslides affecting the route, including both recent and historical events. The inventory is based on the review of multiple data sources: (1) regional and local newspapers, (2) social media, (3) technical notes, and (4) reports from national park rangers. Each data source introduces specific biases into the dataset. For instance, technical reports usually provide highly accurate spatial information but often lack precise data on the timing of the events. In contrast, press archives and social media typically offer reliable temporal information, although spatial details are often imprecise. To address these limitations, the methodology incorporates several procedures aimed at extracting objective information from the original sources, assessing data reliability and minimizing inventory bias. These procedures include: (1) use of multiple and complementary data sources; (2) geo-location of landslides based on spatial descriptions and photographic evidence, supported by free online cartographic platforms (Google Maps-Google Street View and Iberpix) and fieldwork; (3) temporal location of the landslides through cross-validation among sources and interviews with park rangers and local residents; and (4) classification of the spatio-temporal data according to a reliability scale. The proposed methodology has proven effective in obtaining objective and sufficiently reliable data, making the resulting inventory suitable for subsequent quantitative analyses and future research.Funding: Research Project “Sensibilización ante los procesos de ladera y mejora de la seguridad en sendas de montaña de los Parques Nacionales: propuesta de innovación para la autoprotección y educación ambiental – SAFETRACK” financed by the University of León.