Table 2 The spatial relationship between landslides and conditioning topographic factors with Frequency Ratio (FR)
No.pixel | No.Landslides (Di) | Area class km/sq. (Ai) | L.Density/class (Di/Ai) | ∑Di/∑Ai | Frequency Ratio | |
Altitude (a.s.l) class | ||||||
1282 - 1400 | 13,008 | 5 | 12.36292584 | 0.404435007 | 1.710574704 | 0.236432239 |
1400 - 1500 | 11,126 | 16 | 10.5742553 | 1.513108919 | 0.88456173 | |
1500 - 1600 | 10,047 | 70 | 9.548763524 | 7.330792078 | 4.285572598 | |
1600 - 1700 | 11,014 | 40 | 10.46780944 | 3.821238839 | 2.23389182 | |
1700 - 1800 | 14,074 | 58 | 13.37606229 | 4.336104209 | 2.534881522 | |
1800 - 1900 | 13,676 | 36 | 12.99779934 | 2.769699629 | 1.61916321 | |
1900 - 2000 | 12,112 | 28 | 11.51135899 | 2.432380053 | 1.421966575 | |
2000 - 2100 | 9303 | 13 | 8.841658909 | 1.470312317 | 0.859542886 | |
2100 - 2200 | 7758 | 12 | 7.373276343 | 1.627499017 | 0.951434049 | |
2200 - 4182 | 72,571 | 6 | 68.97216261 | 0.086991618 | 0.050855199 | |
Slope angle | No.pixel | No.Landslides (Di) | area class km/sq. (Ai) | L.Density/class (Di/Ai) | ∑Di/∑Ai | |
Very gentle | 10,206 | 6 | 9.699878623 | 0.618564441 | 1.710574704 | 0.361612059 |
Gentle | 19,837 | 20 | 18.85327182 | 1.060823829 | 0.620156387 | |
Moderate | 28,151 | 30 | 26.75497581 | 1.121286755 | 0.655502944 | |
Moderately steep | 57,364 | 117 | 54.51928643 | 2.146029555 | 1.254566404 | |
Steep | 41,468 | 85 | 39.41157816 | 2.156726626 | 1.260819899 | |
Very steep | 17,663 | 26 | 16.78708173 | 1.548809997 | 0.905432539 | |
Plan curvature | ||||||
Curvature class | No.pixel | No.Landslides (Di) | area class km/sq. (Ai) | L.Density/class (Di/Ai) | ∑Di/∑Ai | FR |
−11.696_ − 3.068 | 335 | 0 | 0.318387158 | 0 | 1.710574704 | 0 |
-3.068_ − 1.120 | 4729 | 10 | 4.494486185 | 2.224948434 | 1.300702289 | |
-1.120_ − 0.423 | 24,905 | 47 | 23.66994681 | 1.985640288 | 1.160803023 | |
-0.423_0.133 | 78,682 | 121 | 74.78011462 | 1.61807722 | 0.945926078 | |
0.133_0.829 | 54,570 | 89 | 51.86384249 | 1.716031742 | 1.003190178 | |
0.829_3.055 | 11,110 | 17 | 10.55904875 | 1.609993514 | 0.941200352 | |
3.055_13.631 | 358 | 0 | 0.340246575 | 0 | 0 | |
Slope Aspect | ||||||
Bearing class | No.pixel | No.Landslides (Di) | area class km/sq. (Ai) | L.Density/class (Di/Ai) | ∑Di/∑Ai | FR |
North | 17,469 | 31 | 16.6027023 | 1.867165925 | 1.710574704 | 1.091543047 |
Northeast | 6197 | 15 | 5.889687226 | 2.546824547 | 1.488870694 | |
East | 6327 | 23 | 6.013240452 | 3.824892782 | 2.236027911 | |
Southeast | 16,089 | 54 | 15.29113729 | 3.531457404 | 2.064485927 | |
South | 26,672 | 37 | 25.34932027 | 1.459605213 | 0.707006618 | |
Southwest | 31,068 | 44 | 29.52732011 | 1.490145392 | 2.107682382 | |
West | 34,179 | 38 | 32.48404384 | 1.169805095 | 0.55501963 | |
Northwest | 36,688 | 42 | 34.8686211 | 1.204521391 | 0.704161817 | |
Topographic Roughness Index | ||||||
TRI class | No.pixel | No.Landslides (Di) | area class km/sq. (Ai) | L.Density/class (Di/Ai) | ∑Di/∑Ai | FR |
0–0.15 | 162 | 0 | 0.153966327 | 0 | 1.693003957 | 0 |
0.15–0.31 | 1968 | 3 | 1.870405754 | 1.6039301 | 0.947387066 | |
0.31–0.40 | 11,542 | 20 | 10.96962562 | 1.8232163 | 1.076912001 | |
0.40–0.50 | 80,264 | 140 | 76.28366234 | 1.8352554 | 1.084023076 | |
0.50–0.60 | 71,764 | 105 | 68.2051822 | 1.5394725 | 0.909314156 | |
0.60–1.00 | 10,802 | 16 | 10.26632264 | 1.5584938 | 0.920549403 | |
Profile Curvature | No.pixel | No.Landslides (Di) | area class km/sq. (Ai) | L.Density/class (Di/Ai) | ∑Di/∑Ai | FR |
−25.20 - −5.50 | 214 | 0 | 0.203387618 | 0 | 1.710574704 | 0 |
-5.50 - −2.50 | 928 | 0 | 0.881979949 | 0 | 0 | |
-2.50 - −1.12 | 5334 | 10 | 5.069483889 | 1.9725874 | 1.153172315 | |
-1.12 - −0.41 | 25,179 | 44 | 23.93035899 | 1.8386686 | 1.074883552 | |
-0.41 - 0.11 | 71,679 | 101 | 68.1243974 | 1.4825819 | 0.866715682 | |
0.11–2.50 | 70,300 | 129 | 66.81378279 | 1.9307394 | 1.128708002 | |
2.50–5.00 | 822 | 0 | 0.78123655 | 0 | 0 | |
5.00–10.00 | 209 | 0 | 0.19863557 | 0 | 0 | |
10.00–19.30 | 24 | 0 | 0.022809826 | 0 | 0 | |