Movimientos en masa naturales o inducidosnuevas aportaciones al estudio de inestabilidad de laderas en la provincia de León

Résumé

Mass movements are one of the geological processes with major socio-economic impact in the world. The strong topography and high rain-fall concentration in mountainous areas are two of the main determining and triggering factors involved in the slope instability directly affecting the province of León. Until now, much of these mass movements were linked to the natural erosive action. In this work, we have analysed two landslides with similar morphological characteristics and litoestructural imprint in the areas of Ancares and La Cabrera. These valleys are characterized by the presence of Roman gold mining works that affect the entire valley. The geological and geomorphological mapping, and comparative photointerpretation of aerial images at different time records allow us to analyse the determining and triggering factors behind these mass movements, in which the rupture plane is characterised in both cases by the absence of tensile stress cracks and the presence of opposite dipping fresh quartzites and slates across the slope. Also, the existence of aligned depressions, channel structures and the superimposition of excavations on the slipped material, may support an anthropogenic origin for these mass movement, although further studies are needed to clarify their origin and possible relation to human-induced activity.