Asian Journal of Environment and Disaster Management (AJEDM)

Volume 4 Number 2 (2012)

doi: 10.3850/S1793924012001113


Influence of Geological Parameters on Landslide Vulnerability Zonation of Darjeeling Town, in Eastern Himalayas


Bhabani P. Mukhopadhyay1, Souvanic Roy2, Susanta Chaudhuri3 and Soumen Mitra4
1Professor, Department of Earth Sciences, Bengal Engineering and Science University, Shibpur, Howrah 711103, West Bengal, India.
bpmbesus@gmail.com
2Professor & Director, School of Ecology, Infrastructure & Human Settlement Management,Bengal Engineering and Science University, Shibpur, Howrah 711103, West Bengal, India.
3Assistant Professor, Department of Civil Engineering, College of Engineering Roorkee, Roorkee, Uttrakhand, India.
4Assistant Professor, Department of Architecture, Town and Regional Planning, Bengal Engineering and Science University, Shibpur, Howrah 711103, West Bengal, India.

ABSTRACT

Landslides and related phenomena are common occurrence in and around Darjeeling Town of Eastern Himalayas, West Bengal, India. Reckless destruction of forests along with unscientific construction works coupled with adverse geological factors, rainfall and slope modifications have changed the scenario completely. Due to unprecedented growth of population during the last few decades in the Darjeeling hill areas, nature has started reacting sharply to the accumulated human guilt. Landslide hazards, especially during rainy season have become a common occurrence to the people of the hill causing an extreme damage to the prevailing echo system, human life and public property. In the present study an attempt has been made to propose a landslide vulnerability zonation map of Darjeeling municipal town based on the geological field study encompassing the area of the town. Investigation was carried out mainly on geological and related aspects, those are having a direct influence on slope failure. Studied parameters of the investigation include mainly the lithology, over all structure and orientation of the rock strata, soil type, surface-slope and vegetations. Sumtotal weighted values of all the investigated geological and related parameters were estimated for individual location and vulnerability of the locations towards landslide was scaled against that calculated weighted values. As a whole, for better understanding and suitable zonations of landslide vulnerable areas, all the locations were grouped into three main category as ‘High’; ‘Moderate’; and ‘Low’ according to the proportionate vulnerability towards the slope failure. Finally a landslide vulnerable zonation map of the town has been proposed based on the influences of geological and related parameters of the area. The parameters studied, include only themajor internal factors responsible for slope instability and the proposedmap may served as an important thematic layer to prepare the final hazard zonation map of the town considering the other external and anthropogenic factors influence slope failure.

Keywords: Darjeeling town, Geological field study, Landslide hazards; Vulnerability zonation map.



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