Digital Geology - Mass Movement theme

Mass movement example

Mass movement deposits on BGS geological maps are primarily superficial deposits that have moved down slope under gravity to form landslips. These affect bedrock, other superficial deposits and artificial ground. Various landslip types are recognised but they are rarely classified on BGS maps apart from specialised maps for applied geology.

For DiGMapGB and related purposes, mass movement information is placed in a separate theme. Here it also includes foundered strata, where the ground has collapsed due to subsidence. In the BGS Rock Classification Scheme Volume 4, though, foundered ground is excluded from the mass movement deposits.

Caution must be exercised using the mass movement theme because of the potential hazard caused by ground instability. BGS has not always mapped mass movement deposits and they may occur in places where none are mapped. Even on maps where landslips are recorded it is impossible to be sure that all occurrences were found. It is therefore useful to know the location of potential landslip areas such as determined in some applied geological mapping projects.

In addition to the mapped landslides, BGS has used GIS techniques integrating geological and topographical information, to create a Natural Hazards (GeoSure) dataset which gives an indication of likely slippage by finding, for example, the incidence of clays on steep slopes. This national dataset covers all of Great Britain. Further information is available on the BGS GeoSure pages.