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خانه مقالات-Article مقالات مکانیک-Mechanical Articles سیستم فازی-Fuzzy Systems Landslide hazard zonation mapping using frequency ratio and fuzzy logic approach, a case study of Lachung Valley, Sikkim
Landslide hazard zonation mapping using[taliem.ir]

Landslide hazard zonation mapping using frequency ratio and fuzzy logic approach, a case study of Lachung Valley, Sikkim

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Sikkim Himalaya is under consistent distress due to landslides. Abrupt thrust on infrastructure
development in the valley regions of Sikkim Himalaya has led to a need for a prior planning to face landslide
hazard. A comprehensive study for the identification of landslide hazard zones using landslide frequency ratio and
fuzzy logic in GIS environment has been presented for the Lachung valley, Sikkim, India, where a number of
hydroelectric projects are proposed.

توضیحات محصول

ABSTRACT

Sikkim Himalaya is under consistent distress due to landslides. Abrupt thrust on infrastructure development in the valley regions of Sikkim  Himalaya has led to a need for a prior planning to face landslide hazard. A comprehensive study for the identification of landslide hazard zones  using landslide frequency ratio and fuzzy logic in GIS environment has been presented for the Lachung valley, Sikkim, India, where a number of hydroelectric projects are proposed. Temporal remote sensing data was used to generate significant landslide causative factors in addition to  landslide inventory. Primary topographic attributes namely slope, aspect and relative relief were derived from digital elevation model. Landslide  frequency ratio approach was adopted to correlate landslide causal factors with landslide incidences. Further, fuzzy logic method was used for  the integration of landslide causative factors in order to delineate the landslide hazard zones. Fuzzy memberships were derived from the landslide  frequency ratio values. Different gamma values were used in fuzzy gamma integration process, which resulted different landslide hazard index  maps. Receiver operating characteristic curves were prepared to analyze consistency of the resulting landslide hazard index maps. Landslide  frequency ratio values have emphasised the importance of factors/classes in landsliding. High slope angle (35°-45°), very high slope category  (>45°), High and very high relative relief categories; south, southeast and southwest aspects; drainage and lineaments buffer range of 0-50m,  50-100m and 100 to 150m; quartzite/ garnet schist and migmatite type of lithology; Sandy loam and Rock/loam classes of soils; fallow land and  sparse vegetation classes of land use/land cover were found to be associated with landsliding. Five landslide hazard zonation maps with each comprising five relative landslide hazard zones namely; very low, low, moderate, high and very high hazard zones were prepared by using five  fuzzy gamma operators. Maps indicated that steep talus slopes, close proximity to drainages, ridges and spars fall under high hazard zones.  Settlement areas were observed in low to moderate hazard zones. Very high hazard zones were observed in steep slopes, cliffs and cut slopes  excavated for the roads. Low hazard zones were observed in agricultural terraces and permafrost areas. Hence it can be concluded that  landslide causative factor’s integration using fuzzy logic has yielded good results for Lachung valley. Frequency ratio method for determination of  fuzzy membership value has reduced subjectivity in the model. The final LHZ map (γ = 0.92) can be used for the planning of future  infrastructure, settlement and ecological development in Lachung region

INTRODUCTION

Landslide is a result of a wide variety of geo-environmental processes, which include geological, meteorological and human factors. The main  factors which influence landslides were discussed by Varnes (1984) and Hutchinson (1995). Most important inherent factors are bedrock  geology (lithology, structure, degree of weathering), geomorphology (slope gradient, aspect, and relative relief), soil (depth, structure,  permeability, and porosity), land useland cover, and hydrologic conditions. Landslides are triggered by many extrinsic causative factors such as  rainfall, earthquake, blasting and drilling, cloudburst, flash-floods (Anbalagan 1992). Present study area is a part of Sikkim Himalaya, which is  consistently subjected to landslides during monsoon season. The Himalaya has highly undulating terrain, which is witnessing ongoing orogeny.  In addition to that, during monsoon period the present area receives high precipitation.

Year: 2015

Publisher :  Springer

By : Rathinam Anbalagan, Rohan Kumar , Kalamegam Lakshmanan, Sujata Parida and Sasidharan Neethu

File Information: English Language/ 17 Page / size: 1,848 KB

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سال : 2015

ناشر :  Springer

کاری از : Rathinam Anbalagan, Rohan Kumar , Kalamegam Lakshmanan, Sujata Parida and Sasidharan Neethu

اطلاعات فایل : زبان انگلیسی / 17 صفحه / حجم : KB 1,848

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