|
|
|
Prioritization of landslide hazard zones in parts of Darjeeling district, West Bengal, India- a RS and GIS approach
S. Sudhakar1, B.
Sadasivarao2, B. Suryaprakasa Rao2 and V. Venkateswara
Rao2
1Regional Remote Sensing Service Centre,
Department of Space, Indian Space Research Centre, Indian Institute of
Technology Campus, Kharagpur - 721 302
2Department of
Geo-Engineering, Engineering College, Andhra University, Visakhapatnam - 530017
In India, the incidence of landslides in Himalayas and
other hill ranges is an annual phenomenon. The factors, which promote
landslides, are (i) water (ii) slopes (iii) nature of rock (iv) structure (v)
vegetation (vi) seismic activity. The essential conditions, which cause
landslides, are lack of support in front and lubrication behind. Among natural
hazards, mass movements are the most frequent and have the largess geographical
distribution. Landslides alone cause greater loss of human lives and economic
goods than any other single natural hazards. An integrated Remote Sensing and
Geographical Information System approach is increasingly being used and
recommended for landslide prone zoning. IRS - 1D LISS III satellite data were
used to generated landuse/landcover, digital terrain model for sloe/aspect. The
buffer of road and stream network was generated through on line digitization
from the satellite data. The collateral data of lithology and soil maps were
digitized and integrated with all the layers under study. In the present study,
a quantitative approach for the landslide Hazard Zone (LHZ) mapping has been
used, which more or less follows a numerical rating scheme called Landslide
Hazard Evaluation Factor (LHEF) rating scheme. The LHEF rating scheme is based
upon an empirical approach, which combines past experience, gained from the
study of conditioning factors and their influence on slope stability. It is a
numerical system based on major inherent conditioning factors of slope
instability such as geology, Slope, relative relief, soil and existing landuse
and landcover in the study area.
|
|
|