Landslide Susceptibility Assessment Using Frequency Ratio Technique with Iterative Random Sampling

Table 2

The multicollinearity diagnosis indexes for factors and frequency ratio (FR) values by 10 iterations of training data (TD) (bold FR values mean 1 > of FR value; FR calculations are shown in Table 3).

Factor	Class	Tolerance	VIF	Number of pixels	% of class	FR by 1st TD	FR by 2nd TD	FR by 3rd TD	FR by 4th TD	FR by 5th TD	FR by 6th TD	FR by 7th TD	FR by 8th TD	FR by 9th TD	FR by 10th TD	Min. of FR	Max. of FR	Mean of FR
Slope gradient	0–4.52	0.14	6.94	587838	30.64	0.08	0.00	0.00	0.08	0.08	0.08	0.08	0.08	0.08	0.08	0.00	0.08	0.06
	4.53–7.26			193369	10.08	0.48	0.48	0.48	0.24	0.48	0.24	0.00	0.24	0.00	0.48	0.00	0.48	0.31
	7.27–11.30			184261	9.60	0.00	0.25	0.51	0.00	0.25	0.51	0.25	0.51	0.00	0.51	0.00	0.51	0.28
	11.31–15.79			199096	10.38	0.71	0.47	0.47	0.71	0.47	0.24	0.47	0.47	0.71	0.24	0.24	0.71	0.50
	15.80–18.44			185248	9.66	0.25	0.76	0.76	0.25	0.51	0.76	0.25	0.76	1.01	0.51	0.25	1.01	0.58
	18.45–21.80			196464	10.24	1.67	1.67	1.91	1.43	1.67	1.67	1.43	1.43	1.43	2.14	1.43	2.14	1.65
	21.81–26.33			182212	9.50	2.82	2.05	1.80	2.31	2.31	2.57	2.57	2.31	3.08	2.31	1.80	3.08	2.41
	26.34–62.53			189912	9.90	3.94	4.43	4.19	4.93	4.19	3.94	4.93	4.19	3.70	3.70	3.70	4.93	4.21
Plan curvature	Concave	0.74	1.35	440473	22.96	2.55	2.34	2.12	2.44	2.44	2.02	1.81	1.59	2.44	2.02	1.59	2.55	2.18
	Flat			1022631	53.31	0.23	0.23	0.50	0.27	0.46	0.32	0.32	0.41	0.32	0.50	0.23	0.50	0.36
	Convex			455296	23.73	1.23	1.44	1.03	1.23	0.82	1.54	1.75	1.75	1.13	1.13	0.82	1.75	1.31
Aspect	Flat	0.71	1.42	470201	24.51	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	N			200803	10.47	0.47	0.70	0.93	0.70	0.47	0.93	0.70	0.93	0.93	1.17	0.47	1.17	0.79
	NE			171081	8.92	1.37	0.82	1.09	1.37	1.09	0.82	0.55	1.37	0.82	0.82	0.55	1.37	1.01
	E			145731	7.60	2.25	1.93	2.89	1.61	1.61	2.57	2.25	1.28	2.57	1.61	1.28	2.89	2.05
	SE			160910	8.39	4.07	4.07	2.91	4.07	4.65	3.20	4.07	3.78	3.78	3.49	2.91	4.65	3.81
	S			178679	9.31	1.05	0.52	0.79	1.05	1.05	1.31	0.79	1.05	0.79	0.79	0.52	1.31	0.92
	SW			184698	9.63	0.51	0.25	0.76	0.51	0.25	0.25	1.01	1.27	0.76	0.76	0.25	1.27	0.63
	W			176440	9.20	0.53	1.59	0.80	0.80	0.80	0.80	1.59	0.80	0.80	1.06	0.53	1.59	0.95
	NW			229857	11.98	1.02	1.22	1.02	1.02	1.22	1.22	0.41	0.61	0.81	1.22	0.41	1.22	0.98
Midslope position (MSP)	0–0.13	0.81	1.24	192836	10.05	1.46	1.21	1.70	0.97	1.46	1.21	1.70	1.21	1.94	0.73	0.73	1.94	1.36
	0.14–0.25			192834	10.05	2.18	1.94	1.94	2.43	2.43	2.43	2.67	2.67	1.70	2.43	1.70	2.67	2.28
	0.26–0.35			192894	10.05	1.70	1.70	1.46	2.18	1.46	1.46	1.21	1.70	1.94	1.21	1.21	2.18	1.60
	0.36–0.47			192316	10.02	0.97	0.97	1.22	1.22	0.73	1.46	0.73	1.46	1.22	1.46	0.73	1.46	1.14
	0.48–0.57			197554	10.30	0.95	0.95	0.71	0.47	0.71	0.95	1.18	0.95	0.71	0.71	0.47	1.18	0.83
	0.58–0.67			190370	9.92	0.74	0.98	0.74	0.74	0.74	0.98	1.47	0.49	1.23	1.23	0.49	1.47	0.93
	0.68–0.77			191273	9.97	0.73	0.98	0.73	1.22	0.98	0.49	0.24	0.49	0.49	0.73	0.24	1.22	0.71
	0.78–0.83			189560	9.88	0.74	0.74	1.23	0.25	1.23	0.99	0.49	0.49	0.74	0.99	0.25	1.23	0.79
	0.84–0.90			219546	11.44	0.21	0.21	0.21	0.21	0.21	0.00	0.00	0.21	0.00	0.21	0.00	0.21	0.15
	0.91–1.00			159217	8.30	0.29	0.29	0.00	0.29	0.00	0.00	0.29	0.29	0.00	0.29	0.00	0.29	0.18
Topographic position index (TPI)	−28.29 to −5.52	0.54	1.85	191895	10.00	0.98	0.73	0.98	0.73	0.98	0.98	0.73	0.73	0.73	0.98	0.73	0.98	0.85
	−5.51 to −3.50			191856	10.00	0.49	0.98	0.98	0.49	0.98	0.73	0.49	0.73	0.49	0.73	0.49	0.98	0.71
	−3.49 to −2.16			191884	10.00	0.49	0.73	0.24	0.98	0.24	0.49	0.49	0.49	0.49	0.49	0.24	0.98	0.51
	−2.15 to −1.15			191913	10.00	0.24	0.49	0.49	0.49	0.49	0.24	0.24	0.24	0.24	0.24	0.24	0.49	0.34
	−1.14 to −0.40			191973	10.01	0.24	0.24	0.00	0.24	0.00	0.24	0.00	0.49	0.24	0.24	0.00	0.49	0.19
	−0.39–0.00			222180	11.58	0.21	0.21	0.21	0.00	0.21	0.21	0.00	0.00	0.21	0.00	0.00	0.21	0.13
	0.01–1.00			184177	9.60	1.27	0.51	1.27	0.76	0.76	0.76	1.27	1.02	0.51	0.76	0.51	1.27	0.89
	1.01–3.43			184220	9.60	1.52	1.52	1.27	1.78	2.03	2.03	2.29	2.03	2.03	2.54	1.27	2.54	1.90
	3.44–7.28			184167	9.60	2.79	2.54	2.79	3.05	2.54	2.29	2.54	2.79	3.05	2.54	2.29	3.05	2.69
	7.29–30.27			184135	9.60	2.03	2.29	2.03	1.78	2.03	2.29	2.29	1.78	2.29	1.78	1.78	2.29	2.06
Stream power index (SPI)	0–0.30	0.14	7.02	956705	49.87	0.34	0.49	0.34	0.29	0.34	0.44	0.39	0.39	0.49	0.39	0.29	0.49	0.39
	0.31–0.64			195189	10.17	0.96	0.96	1.20	1.44	1.20	0.48	1.44	1.20	1.20	0.96	0.48	1.44	1.10
	0.65–1.08			191396	9.98	1.71	1.47	2.20	1.47	1.22	1.71	0.98	1.47	0.98	2.20	0.98	2.20	1.54
	1.09–1.59			191237	9.97	1.71	2.20	1.22	2.45	1.71	1.96	2.45	2.94	1.96	2.20	1.22	2.94	2.08
	1.60–2.34			191242	9.97	1.96	1.47	1.22	1.47	1.96	1.96	1.96	1.47	2.20	1.71	1.22	2.20	1.74
	2.35–12.74			192631	10.04	1.94	1.46	2.43	1.70	2.19	1.70	1.21	0.97	1.21	0.97	0.97	2.43	1.58
Topographic wetness index (TWI)	4.43–5.47	0.11	8.49	195462	10.19	5.51	5.03	5.51	5.27	4.31	4.31	5.51	4.55	5.03	4.79	4.31	5.51	4.98
	5.48–5.67			187422	9.77	2.25	2.00	2.00	3.00	2.75	3.25	2.50	2.75	1.75	2.25	1.75	3.25	2.45
	5.68–5.86			198082	10.33	0.24	1.18	0.24	0.24	0.47	0.71	0.94	0.47	0.94	0.71	0.24	1.18	0.61
	5.87–6.07			187444	9.77	1.00	0.50	0.50	0.25	0.75	0.25	0.25	1.00	1.25	0.75	0.25	1.25	0.65
	6.08–6.35			191019	9.96	0.98	0.98	1.47	1.22	1.47	1.22	0.73	0.98	0.98	1.22	0.73	1.47	1.13
	6.36–6.73			192213	10.02	0.00	0.24	0.24	0.00	0.24	0.24	0.00	0.24	0.00	0.24	0.00	0.24	0.14
	6.74–7.19			192409	10.03	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	7.20–7.66			191741	9.99	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	7.67–no data			382608	19.94	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Soil thickness (unit: cm)	<20	0.81	1.24	269442	14.05	0.35	0.35	0.52	0.35	0.35	0.17	0.17	0.35	0.00	0.17	0.00	0.52	0.28
	20–50			184425	9.61	1.52	1.78	1.52	1.27	2.03	2.03	1.01	1.78	1.27	1.78	1.01	2.03	1.60
	50–100			940929	49.05	1.24	1.14	1.24	1.24	1.19	1.14	1.44	1.19	1.49	1.29	1.14	1.49	1.26
	>100			451703	23.55	0.83	0.93	0.73	0.93	0.73	0.93	0.73	0.83	0.62	0.73	0.62	0.93	0.80
	No data			71901	3.75	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Soil material	Gneiss residuum	0.57	1.74	1076813	56.13	1.35	1.26	1.35	1.26	1.35	1.26	1.43	1.26	1.39	1.35	1.26	1.43	1.33
	Granite Residuum			128052	6.67	0.37	0.73	0.73	0.73	0.73	0.73	1.10	1.10	0.73	0.37	0.37	1.10	0.73
	Acidic Residuum			433895	22.62	0.75	0.97	0.65	0.97	0.75	0.97	0.54	0.86	0.65	0.97	0.54	0.97	0.81
	River			207739	10.83	0.45	0.23	0.45	0.23	0.23	0.23	0.00	0.23	0.23	0.00	0.00	0.45	0.23
	No data			71901	3.75	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Topography	Mountainous area	0.67	1.50	650359	33.90	0.58	0.79	0.72	0.58	0.86	0.94	0.79	0.86	0.79	0.79	0.58	0.94	0.77
	Fluvial plains area			202488	10.56	0.46	0.23	0.46	0.23	0.23	0.23	0.00	0.23	0.23	0.00	0.00	0.46	0.23
	Valley area			405521	21.14	0.92	1.15	0.81	1.27	0.92	1.15	0.92	1.15	0.92	1.04	0.81	1.27	1.03
	Hilly area			465206	24.25	2.31	1.81	2.11	2.11	1.91	1.61	2.21	1.71	2.11	2.01	1.61	2.31	1.99
	Alluvial fan area			35874	1.87	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	Piedmont slope area			81800	4.26	0.00	0.57	0.57	0.00	0.57	0.57	0.00	0.57	0.00	0.57	0.00	0.57	0.34
	Diluvium area			5251	0.27	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	No data			71901	3.75	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Timber diameter	Very small	0.13	7.57	35455	1.85	10.56	11.88	10.56	11.88	11.88	11.88	9.24	14.52	10.56	11.88	9.24	14.52	11.48
	Small			100945	5.26	5.56	5.56	4.64	5.56	6.03	5.10	6.49	5.10	5.56	6.03	4.64	6.49	5.56
	Medium			861368	44.90	1.03	1.03	1.25	1.03	0.98	1.09	0.98	0.92	1.09	0.98	0.92	1.25	1.04
	Large			33512	1.75	2.79	1.40	0.00	1.40	1.40	1.40	2.79	2.79	1.40	1.40	0.00	2.79	1.68
	No data			887120	46.24	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Timber density	Loose	0.13	7.57	39728	2.07	9.42	10.60	9.42	12.96	10.60	10.60	8.24	12.96	9.42	10.60	8.24	12.96	10.48
	Moderate			118023	6.15	2.78	3.17	3.17	3.57	2.78	3.17	4.36	2.78	2.78	4.76	2.78	4.76	3.33
	Dense			873529	45.53	1.39	1.29	1.34	1.23	1.34	1.29	1.23	1.23	1.39	1.07	1.07	1.39	1.28
	No data			887120	46.24	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
Lithology	Qa	0.96	1.04	403382	21.03	0.23	0.12	0.12	0.23	0.12	0.12	0.35	0.35	0.00	0.00	0.00	0.35	0.16
	PCEggn			1946	0.10	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	PCEpgn			13277	0.69	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	PCEqf			257984	13.45	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00	0.00
	PCEbgn			1241811	64.73	1.47	1.51	1.51	1.47	1.51	1.51	1.43	1.43	1.54	1.54	1.43	1.54	1.49

Number of training data: 41 landslide occurrences. Abbreviations of Lithology. Qa: Alluvium; PCEggn: Granite Gneiss; PCEpgn: Porphyroblastic Gneiss; PCEqf: Quartzofeldspathic Gneiss; PCEbgn: Biotite Gneiss.