Geophysical Anatomy of the Hollin Hill Landslide, North Yorkshire, UK

Geophysical methods are playing an increasingly important role in the investigation and monitoring of landslides; such methods are proving to be particularly effective for revealing the 3D structure, failures surfaces, and the hydrogeological regimes associated with rock and earth slides. In this paper we present the results of a geoelectrical reconnaissance survey of the Hollin Hill landslide, UK. This work was undertaken in advance of the installation of a permanent geophysical and geotechnical monitoring system, and was designed to assess the suitability of resistivity (resistivity mapping and 2D/3D ERT) and self-potential methods (profiling and mapping) for investigating and monitoring this site. In particular, we were concerned to assess the electrical property contrasts and the magnitude of SP response across the study area. The surveys revealed that there was a good resistivity contrast between the slipped material and sandstone bedrock, which allowed us to use resistivity mapping data and ERT models to define the geometry of the landslide. An SP signature consistent with the movement of groundwater through the landslide was observed at the site, and was used to identify seepage patterns associated with the slipped material.