Geological and land instability mapping using a GIS package as a building block for the development of a risk assessment procedure

A modern land instability risk assessment procedure must include an accurate geological framework and land instability database. Geological and land instability mapping of the northern suburbs of the City of Wollongong represents a considerable challenge and is to be achieved using computer generated 1:4000 topographic base maps. Using an integrated series of techniques, including computer modelling of the escarpment geology and field mapping techniques, a new series of geological maps has been produced. Meanwhile an exhaustive land instability database of the region has been compiled. A flexible approach to mapping and data compilation is very useful and confirms the viability and resourcefulness of a computer based Geographic Information System package. The second stage of this research project (outside the scope of this paper) is the development and validation of a risk assessment procedure. Validation will generally involve steps to test the assessments on the basis of field observations.