Mass-Movement Activity: An Illustration of Differing Responses to Groundwater Conditions From Two Sites in Northern Ireland

Field investigation of slope failure in north-eastern Ireland, at Kilkeel, Co. Down, and Minnis North, Co. Antrim, suggests that groundwater level is an important factor influencing the incidence of failure. However, the pattern of mass-movement in slopes of glacial origin at Kilkeel compared to the Lias clays of Minnis North implies that different types of mass-movement demonstrate different responses to general groundwater conditions. These observations indicate that the traditional formulas used by geomorphologists for soil mechanics problems may need to be modified with respect to the observed character of groundwater conditions.