Geoscience Reference
In-Depth Information
Table 7.2 Landslide triggering factors and determined prioritized factor weights
Factors
1
2
3
4
5
6
7
8
9
10
Prioritized
rating
Slope
1
2
3
4
5
6
7
8
9
9
0.2944
Lithology
1/2
1
2
3
4
5
6
7
8
9
0.2150
Drainage
1/3
1/2
1
2
3
4
5
6
7
8
0.1537
Lineament
1/4
1/3
1/2
1
2
3
4
5
6
7
0.1087
Curvature
1/5
1/4
1/3
1/2
1
2
3
4
5
6
0.0764
UCA
1/6
1/5
1/4
1/3
1/2
1
2
3
4
5
0.0535
RCA
1/7
1/6
1/5
1/4
1/3
1/2
1
2
3
4
0.0375
LULC
1/8
1/7
1/6
1/5
1/4
1/3
1/2
1
2
3
0.0266
Settlement
density
1/9
1/8
1/7
1/6
1/5
1/4
1/3
1/2
1
2
0.0193
Slope aspect
1/9
1/9
1/8
1/7
1/6
1/5
1/4
1/3
1/
2
1
0.0149
CI = 0.0615; R.I (random index) = 1.49 and CR = 0.0413 (consistent). RCA road contributing area; UCA
upslope contributing area; LULC land use and land cover
Source Saaty ( 1980 )
CI
¼ k Max
n/n
1
ð 7 : 3 Þ
Saaty and Vargas ( 2001 ) randomly produced reciprocal matrices using scales 1/9, 1/8,
1/7,
, 8, 9 to evaluate a so called random consistency index (RI). The average
RI of 500 matrices is given in Table 7.3 .
,1,
7.2.1.5 Frequency Ratio Model and Prioritized Class Rating Value
Frequency ratio (FR) model is also a well accepted and popular quantitative
approach for the preparation of landslide susceptibility map. Lee and Talib ( 2005 ),
Pourghasemi ( 2007 ), Lee and Pradhan ( 2007 ), Jadda ( 2009 ), Avinash and
Ashamanjari ( 2010 ), Intarawichian and Dasananda ( 2011 ) successfully applied
'
model to generate landslide susceptibility zoning map. To obtain frequency
ratio (FR) for each class of all the data layers a combination has been established
between landslide inventory map and criterion maps using following equation.
FR
'
N pix Sið ðÞ N pix Nið ðÞ
P N pix Sið ðÞ P N pix Nið ðÞ
Fr i ¼
ð 7 : 4 Þ
N pix Sið ðÞ The number of pixels containing slide in each class (i),
N pix ð N i Þ Total number of pixels having class (i) in the whole watershed,
P N pix Sið ðÞ Total number of pixels containing landslide,
P N pix Nið ðÞ Total number of pixels in the whole area of the watershed.
 
Search WWH ::




Custom Search