Application of Analytical Hierarchy Process (AHP) and Frequency Ratio (FR) Model in Assessing Landslide Susceptibility and Risk - Semi-quantitative Approaches for Landslide Assessment and Prediction - page 218

Table 7.11 Accuracy assessment/comparison of landslide susceptibility with field data
Landslide hazard
risk class

Classi ed
total

Number
correct

Producers
correct

Users accu-
racy (%)

Accuracy
total (%)

Very low 0.00 1 0 - -

Low 0.00 1 0

- -

Moderately low 0.00 3 0

- -

Moderate 19 17 15 78.95 88.24

Moderately high 8 6 5 62.50 83.33

High 17 16 16 94.12 100.00

Very high 6 6 6 100.00 100.00

Total 50 50 42

Overall classification accuracy = 92.89 %
Overall Kappa statistics = 0.8929

7.3.4 Accuracy Result of Landslide Hazard Risk Map

The comparison between assumed true data and randomly selected data from the
classi -

cation accuracy is 92.89 % and overall Kappa Statistics is 0.8929 %. The class wise
accuracy result is shown in Table 7.11 that indicates acceptable results.

ed image has been made on GIS Platform that shows the overall classifi-

7.4 Conclusion

Very fragile and fragmented lithological composition helped easy percolation of
rain water that generated adequate pore-water pressure for promoting downward
movement of slope materials at Paglajhora and Tindharia. The combinations of
moderate to high intensity of risk elements and human intervention associated with
all favourable geomorphic and geo-hydrologic landslide triggering factors have
recognized Lower Paglajhora, Tindharia and Shiviter as high to very high landslide
hazard risk zone in the Shivkhola Watershed. The calculated critical rainfalls of two
major landslide prone parts of the Shivkhola watershed are 105.88 mm/day
(Shiviter T.E.) and 88.93 mm/day (Lower Paglajhora) after Borga et al. ( 1998 ). Log
probability analysis after Chow ( 1951 , 1954 , 1964 ) shows that the rainfall of
90.539 mm is expected at the recurrence interval of 1.01 year with 99 % proba-
bility. This revealed high-potentiality of slide at these locations. Not only that, the
slope steepening caused by road-cut benches and toe erosion, plying of heavy
loaded vehicles, depletion of forest cover in a rapid pace, continuous and regular
orographic rainfall in rainy season, easy percolation of water through fragmented
rock-soil composition and increase pore water pressure have caused destructive
slope failure at all these three locations.