*4.7.2 Weighted overlay model*

Weighted Overlay Model (WOM) was used as a second statistical method for Landslide Risk mapping. Weighted overlay model uses the ranking method to classify each causative factors based on its degree of importance for landslide initiation and each sub factor is classified into sub categories at a scale of 1 to 5 where 1 indicating the very low risk and 5 indicates very high risk. Six causative factors namely LULC, Geology, Geomorphology, Soil (**Table 11**) etc. was used. The factors are then processed in the GIS environment to derive fuzzy logic based landslide risk mapping (**Figure 11**).

The results retrieved from the WOM model reveals 55% of the Tehsil comes under very low category. Low and Moderate category covers about 31.4% and 10.6% of the study area. High and Very High category cover a total of 1.9% together. Most of the low category indicators are located along the Forest and Agricultural areas that include plantations. Slope and settlements covers a major part of Moderate to Very High vulnerable areas.

**151**

**5. Conclusion**

**Figure 11.**

**Table 11.**

**Acknowledgements**

India for funding this research project".

*Weighted overlay model based landslide risk assessment.*

*Comparative Evaluation of Various Statistical Models and Its Accuracy for Landslide Risk…*

**Sl. no Landslide risk class Area (sq.km) Percent coverage (%)** Very low 205.726 55.90% Low 115.829 31.47% Moderate 39.028 10.61% High 6.547 1.78% Very high 0.876 0.24%

368 100.00%

The research reveals the landslide risk mapping of the study area through Weighted Overlay and Fuzzy logic models. Fuzzy model classified a total of 9.1% and 0.4% of the area under moderate and high risk categories whereas Weighted Overlay model classified a total of 10% and 2% area under moderate and high to very high risk categories. Both the statistical model covers Forest and Agricultural areas under Very Low to Low Risk factor. Areas located along barren lands, Settlements and Roadways are classified under moderate to Very High risk areas for mass movements.

"The research work done is a part of NRDMS-DST funded research project. We would like to express our sincerest gratitude to NRDMS-DST, GOI, New Delhi,

*DOI: http://dx.doi.org/10.5772/intechopen.94347*

*Weighted overlay based landslide risk categories.*

*Comparative Evaluation of Various Statistical Models and Its Accuracy for Landslide Risk… DOI: http://dx.doi.org/10.5772/intechopen.94347*


#### **Table 11.**

*Slope Engineering*

**Table 10.**

*Fuzzy logic landslide risk categories.*

**150**

(**Figure 11**).

**Figure 10.**

*4.7.2 Weighted overlay model*

*Fuzzy logic based landslide risk assessment.*

Very High vulnerable areas.

Weighted Overlay Model (WOM) was used as a second statistical method for Landslide Risk mapping. Weighted overlay model uses the ranking method to classify each causative factors based on its degree of importance for landslide initiation and each sub factor is classified into sub categories at a scale of 1 to 5 where 1 indicating the very low risk and 5 indicates very high risk. Six causative factors namely LULC, Geology, Geomorphology, Soil (**Table 11**) etc. was used. The factors are then processed in the GIS environment to derive fuzzy logic based landslide risk mapping

**Sl. no Landslide risk class Area (sq.km) Percent coverage (%)** Very low 247.8 67.34% Low 84.9 23.07% Moderate 33.6 9.13% High 1.7 0.46%

368 100.00%

The results retrieved from the WOM model reveals 55% of the Tehsil comes under very low category. Low and Moderate category covers about 31.4% and 10.6% of the study area. High and Very High category cover a total of 1.9% together. Most of the low category indicators are located along the Forest and Agricultural areas that include plantations. Slope and settlements covers a major part of Moderate to

*Weighted overlay based landslide risk categories.*

**Figure 11.**

*Weighted overlay model based landslide risk assessment.*
