Table 4 Frequency ratio value calculation.

From: Landslide susceptibility assessment using hybrid geospatial, frequency ratio, and AHP models in Souk Ahras province, Northeastern of Algeria

Geo-environmental Criteria

Sub-criterion (with ranges)

Area (km2)

No. of pixels

% of pixels

No. Of landslide

FR

RFFRi

PVj

rainfall

300–400

228,12

22,804

0,054

3

0,22

0,040,123

1,26,558,351

400–500

1309,02

130,908

0,310

17

0,22

0,039,607

 

500–600

1224,53

122,455

0,290

34

0,47

0,084,682

 

600–700

906,03

90,599

0,214

111

2,07

0,373,669

 

700–800

561,28

56,123

0,133

85

2,56

0,461,919

 

Lithology

Alluvium

1389,48,351

18,412

0,33

43

0,52

0,057,073

1,03,218,993

Limestone

202,205,427

2702

0,05

24

1,92

0,210,242

 

Conglomerate

756,3759

10,013

0,18

47

1,04

0,114,368

 

Sandstone

418,802,478

5552

0,10

32

1,28

0,140,161

 

Gypsum

267,721,389

3544

0,06

55

3,67

0,401,504

 

Marlstone

1194,3913

15,812

0,28

49

0,70

0,076,651

 

Distance from faults

 < 50

1 791,91

26,928

0,42

119

1,12

0,335,764

1,12,446,732

50–200

1 286,15

19,439

0,31

96

1,26

0,375,223

 

200–500

672,97

10,030

0,16

31

0,79

0,234,829

 

500–1000

370,40

5609

0,09

4

0,18

0,054,183

 

 > 1000

107,56

1624

0,025

0

-

0,000000

 

LULC

Water

31,1,225,758

385,417

0,007

1

0,54

0,069,140

0,87,123,794

Forest

697,577,733

8,647,090

0,165

75

1,82

0,231,126

 

Build up area

40,8,633,819

532,642

0,010

7

2,75

0,350,204

 

Agricultur

1125,68,316

13,928,627

0,266

82

1,23

0,156,879

 

Low vegetation

596,719,386

7,403,777

0,141

37

1,05

0,133,170

 

Bare land

1737,01,376

21,504,067

0,410

48

0,47

0,059,481

 

NDVI

-0.4—-0.02

2,94

36,284

0,00,070

1

5,71

0,583,239

1,62,883,732

-0.01- 0.2

1 260,08

15,527,681

0,29,813

29

0,39

0,039,713

 

0.3 – 0.4

942,35

11,623,508

0,22,317

52

0,93

0,095,129

 

0.5–0.6

1 238,58

15,212,299

0,29,208

109

1,49

0,152,359

 

0.7–0.9

785,04

9,683,593

0,18,592

59

1,27

0,129,560

 

Distance from river

 < 50

1 790,20

25,328

0,422,965,165

140

1,32

0,362,916

1,04,128,821

50–150

1 387,63

19,677,000

0,328,596,239

81

0,99

0,270,275

 

150–250

647,57

9163,000

0,153,017,601

24

0,63

0,171,970

 

250–500

300,32

4250,000

0,070,972,913

1

0,06

0,015,449

 

 > 500

103,26

1464,000

0,024,448,081

4

0,65

0,179,390

 

Distance from roads

 < 50

2123,4694

29,790

0,4975

156

1,25

0,279,337

0,45,021,187

50–250

1215,84,513

17,438

0,2912

56

0,77

0,171,314

 

250–500

553,210,785

7848

0,1311

19

0,58

0,129,106

 

500–1000

246,770,789

3524

0,0588

14

0,95

0,212,103

 

 > 1000

89,6,838,985

1282

0,0214

5

0,93

0,208,139

 

slope

 < 10°

3012,795,432

4 821 430

0,71,370

128

0,72

0,147,038

1,10,648,953

10°-20°

985,8,311,132

1 574 687

0,23,310

100

1,72

0,351,717

 

20°-30°

194,8,117,598

314 998

0,04,663

21

1,802

0,369,224

 

30°-40°

25,47,964,143

41 942

0,00,621

1

0,64

0,132,021

 

40°-50°

1,33,634,866

2 303

0,00,034

0

-

0,000000

 

 > 50°

0,083,530,206

140

0,00,002

0

-

0,000000

 

Elevation

200–500

71,5,845,703

92,788

0,02

7

1,40

0,270,462

0,47,969,437

500–700

527,37,367

683,372

0,12

38

1,27

0,244,704

 

700–1000

2083,77,304

2,700,327

0,49

128

1,04

0,201,861

 

1000–1200

1261,38,053

1,634,622

0,30

67

0,89

0,172,581

 

1200–1500

284,868,187

369,359

0,07

10

0,57

0,110,393

 
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