Some rocks can contain loosely-packed sandy layers that can become fluidised by water flowing through them. Such sands can 'run', removing support from overlying buildings and causing potential damage.
Running sand hazards can occur where excavations in the sand go below the water table, where springs occur at the base of sand outcrops, around leaking drains or mains water supply pipes or in entire sand bodies if vibrated (liquefaction) e.g. by an earthquake.
A property affected by running sand may experience the following problems:
The potential for running sand to be a hazard has been assessed using 1:50 000 scale digital maps of superficial and bedrock deposits. These have been combined with information from scientific and engineering reports. The detailed digital data illustrated in the map are available as attributed vector polygons, as raster grids and in spreadsheet format.