Landsliding on the south east coast of the Isle of Wight: nature, characteristics and causes

Abstract

This comprehensive report conveys the nature, characteristics and causes of landsliding along the south east coast of the Isle of Wight. Landsliding is a major geohazard worldwide and is a major land shaping process on the Isle of Wight especially along its coastline and the island provides a unique opportunity to study this process. This report provides information and data on landsliding in an area of the island which hasn’t received extensive attention compared to other areas such as Ventnor. The report displays a combination of field data involving geological, lithological and geomorphological data and laboratory data in the form of atterberg limits and shear strength parameters. The findings of this report show that the majority of the study area is highly susceptible to landsliding and the lithology and structure of the area is strongly influencing the type of movement involved in a landslide. The type and nature of the geology and lithology of the area are the major preparatory factors allowing landsliding to occur but the triggering mechanisms in the area are inferred to be rainfall and marine processes. This report also highlights variability of the physical properties of failed material and that the material is highly susceptible to new or repeated failures due to its reduction in shear strength. The findings of this report have pronounced implications for the future of the area due to the predicted future changes in climate and rise in sea level and landsliding is predicted to be a continual process shaping the study area and thus a continual geohazard on the island.