Landslide Susceptibility Modeling Manual- Data Preparation & Application of Frequency Ratio Model
Landslide Susceptibility Modeling
(A Manual for Data Preparation and Application of Frequency Ratio Model)
This manual contains stepwise procedure for preparation of landslide susceptibility map using Frequency Ratio Model. Landslide inventory is prepared using Google Earth Pro and the analysis was carried out in MsExcel and ArcMap. The dataset used for this manual can be found upon reasonable request.
Landslide Conditioning Factor
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Landslide conditioning factor selection depends upon several factors such as the geological and topographical characteristics of the area, the type of landslide, the scale of the analysis, and the available data and resources.
Geological and topographical characteristics
Type of landslide
Scale of analysis
Available data and resources.
In general, the selection of landslide conditioning factors should be based on a comprehensive analysis of the site-specific conditions and the available data and resources. This will help to ensure that the most relevant and important factors are included in the analysis and that the results are accurate and reliable.
Some of the examples
Aspect refers to the direction that a slope is facing, and it can have an impact on the amount of sunlight and wind exposure that a slope receives, as well as on the distribution of moisture and vegetation.
Slope is a critical factor in assessing the potential for landslides and slope stability. The angle of inclination of the slope can influence soil or rock strength, the effect of gravity, the infiltration of water, and the growth and distribution of vegetation, all of which can ultimately impact slope stability.
Curvature create zones of weakness (Shear strength reduction: high positive curvature (i.e., convex slopes)), influence water flow and pore pressure, and interact with other slope factors.
The formula for the calculation of Frequency
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𝐅𝐑=(% of landslide pixels in each subclass)/(% of total pixels in the subclass of a factor)=(%LandslidePixels)/(%Class pixels)
𝐅𝐑=(factor class FR)/(∑factor class FR)
To understand the mutual interrelationships among the conditioning factors
𝐏𝐑=(RFmax−RFmin)/(RFmax−RFmin)/Min
Where,
FR: Frequency Ratio
RF: Relative Frequency (Index of the spatial association of spatial factors and landslides
PR: Prediction Rate
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