Measuring deformation related to active sinkholes with ground-based 3D laser scanner. A case study in the evaporite karst of the Ebro Valley, NE Spain

Abstract

The investigations dealing with subsidence monitoring in active sinkholes are very scarce, especially when compared with other ground instability phenomena such as landslides. Recently, satisfactory results have been obtained utilizing some relatively new geodetic techniques such as airborne LiDAR (Light Detection And Ranging) and DInSAR (Differential Synthetic Aperture Radar Interferometry). In this work, carried out in the mantled evaporite karst of the Ebro Valley, NE Spain, we explore the potential of ground-based 3D laser scanner for the detailed characterisation of subsidence activity in specific sinkholes. The practicality of the approach is illustrated through a sinkhole in Alcalá village, which affects a flood-control dike of the Ebro River. This sinkhole with recurrent collapse activity significantly contributes to reduce the mechanical strength of the embankment, leading to high-risk situations during flood events.