Report No. : GEO Report No. 252

Report Title : An Updated Assessment of Landslide Risk Posed by Man-made Slopes and Natural Hillsides in Hong Kong (2010), 46 p.

Author : P.F.K. Cheng & F.W.Y. Ko

Abstract

Landslide risk arising from man-made slopes registered in the Catalogue of Slopes and natural hillsides has been assessed by quantitative risk assessment (QRA). The objective of the current study is to update the landslide risk estimation for the year 2010 in order to facilitate the formulation of future landslide prevention and mitigation programme. This study deals with risk to life only, other types of risk such as economic risk and social impact have not been considered.

The results indicate that the risk level due to man-made slopes for the year 2010 is similar to that estimated in the 2004 study. The latest estimate also shows that by 2010, a major portion of landslide risk arising from man-made slopes will be from old technology slopes and sub-standard slopes of moderate risk.

The update of the landslide risk for natural hillsides involves mainly an enhancement of the failure frequency models using the latest information from the Enhanced Natural Terrain Landslide Inventory and the Historical Landslide Catchment Inventory. The results indicate that the risk level due to natural hillsides in 2010 is comparable to that obtained in the 2004 assessment, despite some changes to the overall landslide risk distributions given the additional information available.

Further development on the QRA models and the ranking methodology for man-made slopes and natural hillsides respectively would be addressed in separate documentations.

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