Landslide hazard analysis for Hong Kong using landslide inventory and GIS

This paper presents a landslide-inventory-based and GIS-based framework for systematic landslide hazard analysis by employing historical landslide data in Hong Kong, coupling with geological, geomorphological, population, climatic, and rainfall data. Based on 1448 landslide data from 1984 to 1998, the diurnal and seasonal distributions of landslides are established and compared with the seasonal rainfall variation. The cumulative fatalities and injuries caused by landslides increase with the cumulative rainfall in Hong Kong, indicating a strong correlation between rainfall and landslide consequences. The average annual fatality and injury rates in Hong Kong caused by landslide are 11.35 and 11.63, respectively. In terms of being hit by a landslide, squatter areas and roads on Hong Kong Island are at the highest risk. A frequency-volume relation for Hong Kong Island was established, and, using this relation, it was estimated that the return period of a 26,000m(3) landslide (the size of 1995 Shum Wan Road Landslide) is about 3.12 years. A hazard zonation map for Hong Kong Island is established by using historical data. The potential use of GIS technology to incorporate various layers of information is illustrated using Hong Kong Island as an example. Both landslide hazard and risk maps are proposed using raster calculation. (C) 2004 Elsevier Ltd. All rights reserved.