Modelling the Motion of Mobile Debris Flows in Hong Kong

  • J. S. H. KwanEmail author
  • T. H. H. Hui
  • K. K. S. Ho


Lantau Island is located at the south-western part of Hong Kong. Over 75 % of its areas are natural hillsides and approximately one third of the hillsides are sloping at 30° or above. The geology comprises tuff and granite. On 7 June 2008, a severe rainfall with a return period of 1,100 years occurred over the western part of Lantau Island. This triggered over 2,400 landslides, about 900 of which were debris flows. Some of these were sizeable and mobile, involving active debris volumes and travel distances in excess of 10,000 m3 and 1,700 m respectively. This paper examines the runout characteristics of selected mobile debris flows. Two-dimensional and three-dimensional dynamic models developed by the Geotechnical Engineering Office (GEO), Civil Engineering and Development Department were used to back analyse the long-runout debris flows, taking into account the complicated geometry of the runout paths. The findings and their engineering implications are presented in the paper.


Landslide Debris flow Numerical modelling 



This paper is published with the permission of the Head of the Geotechnical Engineering Office and the Director of Civil Engineering and Development, Government of the Hong Kong Special Administrative Region.


  1. Hungr O (1995) A model for the runout analysis of rapid flow slides, debris flows and avalanches. Can Geotech J 32:610–623CrossRefGoogle Scholar
  2. Hungr O, Morgenstern NR, Wong HN (2007) Review of benchmarking exercise on landslide debris runout and mobility modelling. In: Proceedings of the international forum on landslide disaster management, vol 2, Hong Kong, pp 945–966Google Scholar
  3. Ko FWY (2005) Correlation between rainfall and natural terrain landslide occurrence in Hong Kong, GEO Report No. 168. Geotechnical Engineering Office, Hong Kong, 77pGoogle Scholar
  4. Kwan JSH, Sun HW (2006) An improved landslide mobility model. Can Geotech J 43:531–539CrossRefGoogle Scholar
  5. Kwan JSH, Sun HW (2007) Benchmarking exercise on landslide mobility modelling – runout analyses using 3dDMM. In: Proceedings of the international forum on landslide disaster management, vol 2, Hong Kong, pp 945–966Google Scholar
  6. Lo DOK (2000) Review of natural terrain landslide debris-resisting barrier design, GEO Report No. 104. Geotechnical Engineering Office, Hong Kong, 91pGoogle Scholar
  7. McDougall S, Hungr O (2005) Dynamic modelling of entrainment in rapid landslides. Can Geotech J 42:1437–1448CrossRefGoogle Scholar
  8. Wong HN (2009) Rising to the challenges of natural terrain landslides. In: Proceedings of the HKIE Geotechnical Division annual seminar on natural hillsides: study and risk management measures. Hong Kong Institution of Engineers, Hong Kong, pp 15–53Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • J. S. H. Kwan
    • 1
    Email author
  • T. H. H. Hui
    • 1
  • K. K. S. Ho
    • 1
  1. 1.Geotechnical Engineering Office, Civil Engineering and Development DepartmentThe Government of the Hong Kong Special Adminstrative RegionHong KongChina

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