Multiple geo-environmental hazards susceptibility assessment: a case study in Luoning County, Henan Province, China

Figures & data

Figure 1. Location map of the study area. Source: Institute of Henan Geological Survey (http://www.hnddy.com/)

Table 1. Basic features of landform of the study area.

Type	Basic features
	Altitude (m)	Height difference (m)	Slope (°)
Middle mountain	1000–2000	300–600	40–60
Low mountain	500–1000	150–300	35–45
Hilly	500–700	100–150	30–50
Loess tableland	400–500	100–150	＜5
River valley terrace	276–400	<50	4–6

Figure 2. Classification of geotechnical engineering rocks group and fault distribution. Source: Institute of Henan Geological Survey (http://www.hnddy.com/)

Figure 3. Types of land use in the study area. Source: Institute of Henan Geological Survey (http://www.hnddy.com/)

Figure 4. Distribution map of geological environmental hazards in the study area. Source: Institute of Henan Geological Survey (http://www.hnddy.com/), Ministry of Land and Resources of PRC (http://www.mnr.gov.cn/)

Table 2. Land use types and their geological environmental effects in study area.

Type	Human engineering activities	Human activity intensity	Geo-environmental effect	Easily induced geo-environmental hazards
Mining land	Open pit slag, tailings, rock failure, groundwater draining, etc.	Stronger	Larger	Soil erosion, goaf collapse, rockfall, landslide
Reservoir land	Reservoir excavation and reservoir storage	Strong	Large	Rockfall, landslide
Urban and rural construction land, road construction land	Cut slopes, waste soil and stone heaps, cave excavation	Stronger	Larger	Goaf collapse, rockfall, landslide
Agricultural land	Dig and fill the land	Commonly	Commonly	Soil erosion
Ecological land	Deforest and mining Resource	Slight	Slight	Soil erosion

Figure 5. Flow chart of this study. Source: Authors

Table 3. The 1–9 scales for pairwise comparisons in the AHP.

Importance intensity	Definition
1	Equal importance
3	Moderate importance of one over another
5	Strong importance of one over another
7	Very strong importance of one over another
9	Extreme importance of one over another
2,4,6,8	Intermediate values
Reciprocals	Reciprocals for inverse comparison

Table 4. Random Consistency Index (RI) (Saaty, 1980, 2000).

n	1	2	3	4	5	6	7	8	9	10
RI	0	0	0.58	0.90	1.12	1.24	1.32	1.41	1.45	1.49

Table 5. Assessment index system of four hazards susceptibility.

Hazard	Attribute value and grade division of evaluation index
	Index grade	4	3	2	1
Landslide	Landform	Low mountain, hilly	Middle mountain	Loess tableland	River valley terrace
	Engineering geology	Qp, double-layered rock mass	Qh	R	γ, Ch, Jx, Arth
	Distance from fault (km）	<0.5	0.5–2	2–5	>5
	Land use	Road construction land, town, mining land	Upland field, orchard	Irrigated cropland, grass land	Forest land, shrub land, river system
	Rainfall (mm/a)	>850	750–850	650–750	＜650
Rockfall	Landform	Middle mountain	Low mountain, hilly	Loess tableland	River valley terrace
	Engineering geology	Qp, Ch, double- layered rock mass	γ, Jx, Arth	R	Qh
	Distance from fault (km）	<0.5	0.5–2	2–5	>5
	Rainfall (mm/a)	>850	750–850	650–750	＜650
	Land use	Road construction land, town, mining land	Upland field, orchard	Irrigated cropland, grass land	Forest land, shrub land, river system
Goaf collapse	Soil type	Qp, double-layered rock mass	Qh	R	γ, Ch, Jx, Arth
	Distance from fault (km）	<0.5	0.5–2	2–5	>5
	Rainfall (mm/a)	>850	750–850	650–750	＜650
	Land use	Town, mining land		Road construction land, upland field, orchard, irrigated cropland	Forest land, shrub land, river system, grass land
Soil erosion	Soil type	Qp, Ch, double- layered rock mass	γ, Jx, Arth	R	Qh
	Landform	Low mountain, hilly	Middle mountain	Loess tableland	River valley terrace
	Rainfall (mm/a)	>850	750–850	650–750	＜650
	Land use	Road construction land, town, mining land	Upland field, orchard	Irrigated cropland, grass land	Forest land, shrub land, river system

Table 6. Pairwise comparison matrix for landslide susceptibility assessment. L1 = Landform, L2 = Engineering geology, L3 = Distance from fault, L4 = Land use, L5 = Rainfall.

	L1	L2	L3	L4	L5	Weight
L1	1	1	3	1	2	0.2671
L2		1	2	1	2	0.2463
L3			1	1/2	1/2	0.0989
L4				1	2	0.2463
L5					1	0.1415
CR = 0.0123

Table 7. Pairwise comparison matrix for rockfall susceptibility assessment. R1 = Landform, R2 = Engineering geology, R3 = Distance from fault, R4 = Land use, R5 = Rainfall.

	R1	R2	R3	R4	R5	Weight
R1	1	1	2	1	2	0.2472
R2		1	2	1	2	0.2472
R3			1	1/3	1	0.1140
R4				1	2	0.2681
R5					1	0.1236
CR = 0.0044

Table 8. Pairwise comparison matrix for goaf collapse susceptibility assessment. G1= Soil type, G2 = Distance from fault, G3 = Rainfall, G4 = Land use.

	G1	G2	G3	G4	Weight
G1	1	1/2	1	1/2	0.1650
G2		1	2	1/2	0.2775
G3			1	1/2	0.1650
G4				1	0.3925
CR = 0.0226

Table 9. Pairwise comparison matrix for soil erosion susceptibility assessment. S1 = Soil type, S2 = Landform, S3 = Rainfall, S4 = Land use type.

	S1	S2	S3	S4	Weight
S1	1	1	2	2	0.3317
S2		1	2	2	0.3317
S3			1	1/2	0.1394
S4				1	0.1972
CR = 0.0226

Figure 6. Single-hazard susceptibility zoning map. (a) Landslide, (b) Rockfall, (c) Goaf collapse, (d) soil erosion. Source: Authors

Table 10. Statistical table of single hazard susceptibility assessment mapping.

Hazard type	Susceptibility level	High	Moderate	Low	Stable
Landslide	Hazard number	44	18	6	0
	Percentages (%)	64.7	26.5	8.8
	Area (km^2)	214.96	1016.47	716.46	376.01
	Area (% of study area)	9.25	43.74	30.83	16.18
Rockfall	Hazard number	28	28	11	4
	Percentages (%)	39.4	39.4	15.5	5.6
	Area (km^2)	136.65	649.30	1354.60	183.36
	Area (% of study area)	5.88	27.94	58.29	7.89
Goaf collapse	Hazard number	2	0	3	1
	Percentages (%)	33.3	0	50.0	16.7
	Area (km^2)	18.82	0	808.25	1496.82
	Area (% of study area)	0.81	0	34.78	64.41
Soil erosion	Area (km^2)	55.77	1145.24	601.89	520.78
	Area (% of study area)	2.4	49.29	25.9	22.41

Figure 7. Comprehensive multi-hazards susceptibility map. Source: Authors

Figure 8. The success-rate results of the single hazard susceptibility maps obtained from the AHP. Source: Authors

Figure 9. Compared the main roads with the comprehensive susceptibility map. Source: Authors

Saaty TL. 1980. The analytic hierarchy process. New York: McGraw Hill. International, Translated to Russian, Portuguese, and Chinese, Revised editions, Paperback (1996, 2000). Pittsburgh: RWS Publications.

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Saaty TL. 2000. Fundamentals of decision making and priority theory with the analytic hierarchy process. Vol. 6. Pittsburgh: RWS Publications.

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