On the impact of urban landslides

Abstract

Abstract Although considerable attention has been paid to the issue of urban landslides in the literature since Alexander's 1989 paper on the topic, few attempts have been made to quantify their importance. In this paper, such an attempt is made, based upon global landslide fatality data from 2005. First, a new definition for the term ‘urban landslide’ is proposed. This is then applied in the analysis of the 2005 landslide fatality data. It is shown that fatal urban landslides occur primarily in the tropical regions, whereas rural landslides dominate the mid- and high-latitude regions. The causes for this are explored using a detailed dataset for landslide fatalities in Nepal during the period 1968–2006. It is proposed that the key difference between the tropical and the extra-tropical regions is that in the case of the former areas, landslides are mostly triggered as a result of disturbance of the thick weathering layers, whereas in the latter case they tend to be shallow, high-energy events triggered by seasonal rainfall. Finally, an analysis is presented of the distribution by latitude of papers presented in the ‘Urban Landslides’ session at the International Association for Engineering Geology and the Environment (IAEG) Congress in 2006. It is shown that the distribution of papers mirrors the distribution of all landslide types, and of the global population, and not the distribution of urban landslides. This suggests that urban landslides in the tropical regions, specifically, are not receiving adequate attention from the research community.