Landslides impact and management on human settlements over 3000 years: the case of the Montilla Castle Hill (Córdoba, Spain)

Abstract

In recent decades, global urbanisation has increased dramatically. The study of urbanised areas over the last millennium offers valuable insight into the long-term landslide hazards associated with human settlements. Anthropogenic environmental impact and urbanisation in southern Iberia began around 2200 yr BCE, rendering this region a unique location to examine interactions between building construction and landslide over millennial timescales. The Montilla Castle Hill, in south Spain, was selected for this study due to its clear evidence of landslides and confirmed historical occupation dating back to the Copper Age. This study adopted a multidisciplinary approach, integrating archaeology, geology, geophysics, geotechnical modelling and related disciplines to characterize construction types and pathologies, as well as landslide ages, critical stability threshold values, landslide mechanisms and key features. The obtained data were compared with regional paleoclimate records and earthquakes/tsunamic events in south Iberia. Four landslide activity phases have been dated: from 650–550 BCE, from 400 to 200 BCE, from 1400 to 1450 and along the XVIII to XX centuries. Observations revealed that the presence of major buildings at the summit of the Castle Hill, at the landslide crown, were a key factor in promoting the reactivation of ancient landslides. This study found no evidence linking climate conditions with slope stability, but a correlation with major regional earthquakes was observed, in agreement with the modelled values obtained.