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Assessing landslide hazard in GIS: a case study from Rasuwa, Nepal

  • G. Acharya
  • F. De SmedtEmail author
  • N. T. Long
Original Paper

Abstract

A slope stability analysis on a regional scale is presented for the northern part of the Rasuwa district in Nepal, covering 409 km2. A physically based slope stability model coupled to a simplified groundwater flow model was used to estimate soil wetness, and safety maps were generated for three steady state and two quasi-dynamic conditions. The results show that only about half of the soils are unconditionally stable, characterised by slopes smaller than 22°. Some 7% of the study area is prone to failure under completely saturated conditions, where the slopes exceed 30° and the land-use is predominantly agricultural. Some deficiencies in the model are discussed, but nevertheless the study shows that based upon relatively coarse and limited data, useful landslide hazard information on a regional scale can be obtained.

Keywords

Slope stability Landslide hazard GIS analysis Wetness index Himalayas 

Résumé

Une analyse de stabilité des terrains est présentée à une échelle régionale, couvrant une surface de 409 km2, pour le nord du district de Rasuwa au Népal. Un modèle de stabilité des terrains, couplé à un modèle simplifié d'écoulement, a été utilisé pour estimer l'humidité des sols et générer des cartes d'aléa, avec trois conditions de régime permanent et deux conditions quasi dynamiques. Les résultats montrent que seulement la moitié de la région étudiée, présentant des pentes inférieures à 22°, n'est pas concernée par cet aléa. Environ 7% de la région présente des risques de glissements de terrain en conditions saturées, avec des pentes supérieures à 30° et un usage agricole des sols. Quelques défauts du modèle sont discutés. Cependant l'étude montre que, avec des données relativement simples et limitées, une information relative au risque de glissement de terrain peut être obtenue.

Mots clés

Stabilité des pentes Aléa glissement de terrain Analyse SIG Indice d'humidité Himalaya 

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Copyright information

© Springer-Verlag 2005

Authors and Affiliations

  1. 1.Department of Hydrology and Hydraulic EngineeringVrije Universiteit BrusselBrusselsBelgium

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