Lower Greensand

Engineering geology

The Lower Greensand is one of the most landslide-susceptible formations in the UK with at least 288 known occurrences in South-East England recorded to the year 2000. Of the formations within the Lower Greensand, the Atherfield Clay is the most prone to landslip. Landslides are occasional, rapid movements of a mass of earth or rock sliding along a steep slope. They tend to occur after sustained heavy rain, when the water saturates overlying rock, making it heavy and liable to slide, others occur via soil creep is a very slow movement, occurring on very gentle slopes because of the way soils repeatedly expand and contract in wet and dry periods. When the soil dries out, it contracts vertically, assisting the soil slowly down a slope.