Natural and induced slope instability associated with large mass movements during the Pleistocene-Holocene in the Serra dos Ancares (NW of the Iberian Peninsula)

Abstract

The Serra dos Ancares is a natural area affected with steep slopes by quaternary glacial processes. The presence of up to 28 landslides has been detected on these slopes in the entire sector studied. The existing landslides had been considered mostly of natural origin, but the data collected indicate that a significant number of them, qualitatively and quantitatively, are anthropogenic in origin. In the 1st century B.C. the Roman Empire occupied the area and, once settled, began to exploit it, due to the presence of gold deposits. The Roman gold extracting activity entailed a series of infrastructures that produced an intense erosion of the land in a short time, inducing multiple landslides. The aim of this work is to establish a classification of the mass movements in the study area, determining factors such as their volume, surface or typology and relating them to their different origins, as well as to determine the impact of natural and anthropic activity in the mountain range, and its imprint on the current landscape.