Rozwój i określenie przyczyn osuwiska na skarpie zbiornika wodnego po odkrywkowej kopalni siarki „Piaseczno”

The landslide in the southern part of the western escarpment of the "Piaseczno" water reservoir was activated on 11th May 2011. The reservoir is a former open-cast sulphur mine and the landslide occurred in its internal dump. The volume of moved soil was estimated at 1 mln m3. The paper presents the development of the landslide that firstly occurred in the lower part of the escarpment and next moved to the upper parts far from the reservoir's boundaries. The landslide movement can be described as a regressive flow of saturated soil mass. The paper also discusses the research on the subject of the landslides and the stability analyses, as well as the influence of various factors.