2. INTRODUCTION
Landslide is the movement of earth, mass of rock or debris
along the slope
Gharwal Himalaya is a part of extra peninsula
Structural disturbances like folding, faulting, and shearing
are very common in this region
This area exhibits variety of landslides because of various
natural as well as artificial activities
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3. INTRODUCTION
Landslides may be ignored if they occur in the area of
no human interest
But if it occur in areas like roads, agricultural lands,
human inhabited areas then it leads to loss of life and
property
Minor to major landslides that are very common near
Pipalkoti area on the road of Chamoli to Joshimath
that have increased the maintenance cost of Rishikesh
–Mana Highway
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4. INTRODUCTION
There is need to study and classify the Himalayan
landslides from road network point of view in
Mountain terrain
This study is done by available Base maps of area and
their interpolation with RS and GIS to form the
landslide hazard zonation maps of respective study
areas
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5. STUDY AREA
3 areas have been selected
a ) Gopeshwar city of Chamoli district
b ) Stretch of Chamoli-Joshimath road near
Pipalkoti
c ) Area around Nandprayag
Area lies in Survey of India toposheet covering
26.18 sq.km, 21 sq.km and 17.63 sq.km respectively
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7. GEOLOGY OF AREA
There is an intense metamorphosis in area
Land consist of rocks such as quartzite, gneisses,
marbles and various types of micaceous schist and
slates
All these rocks have weak cohesion along the plains
Physiographically the area lies in tectonic , folded and
over thrust mountainous chain.
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8. LANDSLIDE
Geography and Geology of this area makes it prone to
landslides
Besides this area comes under zone IV of earthquake
High flow of rivers and ice melting triggers the action
of landslides
Besides this road development across slopes and
deforestation adds effect to landslide.
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9. LANDSLIDES
Following types of landslide was observed in study area
1. Slides
2. Falls
3. Flow
4. Topples
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14. RS AND GIS TECHNIQUE
Field survey is most accurate way to study landslides
But to study large and remote area it is consuming
time and money
RS and GIS are most effective tools in such condition
to obtain results with good accuracy
Various satellite images provided by IKONOS, IRS P6,
QUICK BIRD etc can be used as base to study
landslides.
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15. REMOTE SENSING (RS)
RS data like satellite images and aerial photographs are
used to extract terrain information.
Satellite data of different years gives information about
changes in geomorphology of area.
Various factor maps like land use map, drainage map
etc can be prepared from processing of RS data
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16. GEOGRAPHICAL INFORMATION
SYSTEM (GIS)
GIS has information about different terrain factors in
the form of layers
With use of GIS software like ILWIS it is possible to
combine the factor map produced by RS with
landslide map.
This will visualize landslide density in survey area .
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17. ILWIS
ILWIS (Integrated Land and Water Information
System) is a GIS software developed by ITC,
Netherland.
It contains both the modules of GIS and image
processing
It is very fast and accurate tool for processing,
analyzing and representing spatial data.
It is a useful tool for landslide analysis
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18. Landslide hazard zonation mapping
There is no basis available to forecast the probability of
landslide occurrence in given time period
But landslide hazard assessment is possible
Hazard assessment is the estimation of an area to its
susceptibility to landslide based on few key factors
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19. Landslide hazard zonation mapping
Following data used to measure landslide hazard of an
area:
Past landslides and their distribution
Bed rock properties
Slope of area
Hydrology of area
Human factors
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20. Applications of hazard zonation
It helps to decide land use capability of area
It shows risk to current land use development
It shows area vulnerable to landslide
Based on surveys it helps to predict future landslides
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21. METHODOLOGY
Remote sensing and GIS are two main methodologies
adopted for landslide hazard zonation
Remote sensing data used in the form of satellite
imageries
GIS software is used to interpolate both satellite data
and base maps to form hazard zonation map
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22. RS DATA INTERPRETATION
Digital data of IKONOS is procured from
www.earth.google.comof all study areas.
The color composite is prepared in ILWIS in RGB
bands.
The satellite data is geo-referenced and rectified with
base map of study area.
Base map is prepared by use of toposheets.
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24. GENERATION OF DIGITAL ELEVATED
MODEL (DEM)
Base map is imported to ILWIS and converted to
ILWIS data format
Geo coding and Geo referencing is done to generate a
raster (Images in Geo-Informatics)
The segment maps are digitized in respective domain
boundaries of area, contours and drainage.
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25. GENERATION OF DIGITAL ELEVATED
MODEL (DEM)
DEM is prepared after interpolating the contour
segment data
DEM is analyzed by spatial filtering and slope maps
are derived
From DEM flow direction and flow accumulation map
is also prepared
Degree of map was classified as per Young's
Classification
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28. Generation of hazard zonation map
Satellite data was imported and geo referenced with
base map
The data is then interpreted by image interpretation
keys and pre occurred landslides and landslide hazard
zones are located
The slope map layer, flow map layer, drainage layer are
added on RS data to predict the landslide prone zones
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31. Preparing stereo pairs
From DEM stereo pairs are prepared to view for
various rasters like slope degree map, satellite data etc
The generated stereo pairs are viewed as ANAGLYPH.
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33. CONCLUSION
Landslides are Force Majeure.
When occurred, landslides causes great losses to both
Human and Infrastructure.
Remote Sensing data has proved to be an effective tool
for landslides study in remote areas like Himalayan
ranges.
RS and GIS based Hazard Zonation Maps gives
accurate information about the Risk levels in a
particular area.
GIS techniques found to be very economical for field
study in inaccessible areas.
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