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ANALYSIS OF REGIONAL GEOLOGIC HAZARDS(LANDSLIDE) USING GIS TECHNOLOGY 
Youn-Jong Kim, Won-Young Kim, Il-Hyon Yu 
Environmental Geology Research Group 
Korea Institute of Geology, Mining And Materials(KIGAM) 
30, Kajung-Dong, Yoosung-Ku, Taejon, Korea 
Dong-jo Seo, Young-Kyu Yang 
Systems Engineering Research Institute 
Korea Institute of Science and Technology 
1, Eoeun-Dong, Yoosung-Ku, Taejon, Korea 
ABSTRACT 
A regional geologic hazard map was produced in the suburbs of Seoul Metropolitan area using 
GIS technology, especially to indicate the potential degree of landslides. The elements of 
topography, geology and ‘soil were incorporated on this map through GIS, which were enable 
to predict the potential hazards of landslide. The factors causing a landslide are slope geometry, 
geology, groundwater table, soil property, rainfall and vegetation etc. All these factors were 
considered in our GIS system and the cartographic simulation was conducted to produce a regional 
geologic hazard map. For this work, ARC/INFO and ERDAS systems were used in SUN 4/390 
workstation. 
KEY WORDS : Geologic hazards map, Stability rating system, Landslide occurrence, Isopleth map, 
Unified soil classification system, Rock quality designation. 
INTRODUCTION Comprehensive analyses of the landslide hazards 
require laboratory test of materials, test 
GIS technology was applied for assessments of borings, geophysical prospecting and numerical 
landslide hazards. The final map was produced modelling analyses of potential failure surfaces 
by GIS, showing the prediction of landslide (Kim, Y.J., and Kim W.Y., 31991). However 
occurrence and the assessment of landslide risk this study only concerns regional analysis of 
in the study area. landslides using GIS technology. The study area 
encompasses about 142km“ in the southern 
The first sign of landslide is the appearance part, which is being developed for the 
of surface cracks in the upper part of the construction of new town, of Seoul Metropolis 
slope, perpendicular to the direction of the in Korea. But the hazard map covers only 70 
movement. These cracks gradually fill with km^ of the central part in the study area, 
water, which weakens the soil and increases due to lack of subsurface information. 
the horizontal force which initiates the slide 
(Hans F. Winterkorn et al, 1975). For INITIAL EVALUATION OF LANDSLIDE 
regional hazard analysis, we have examined HAZARDS WITH ISOPLETH MAP 
some environmental factors(Walker, 1987) which : : : 
affect landslide occurrences(geometry of slope, Isopleth mapping of landslide deposits 
vegetation, rainfall, soil texture, geologic and (DeGRAFF, 1985, 1988, Wright et al 1974) 
hydrogeologic influences). This, primarily, can provide economical means for assessing the 
permited us to recognize the spatial and degree of landslide hazards in a large area 
temporal association of landslides with some (Kim, Y.J, and Yu,LH., 1989). But isopleth 
environmental phenomena, and to develop a maps only serve as a simple way to predict 
stability rating system for applying GIS to landslide hazard zonation, although they can be 
assess  landsliding risk in the study area. used to reduce landslide hazards. A isopleth 
Finally, GIS have produced a regional geologic map prepared from areal photographs(May, 
hazard map through cartographic simulation in 1987, 1:10,000 scale) was registered as a data 
conjunction with this rating system. layer in ARC/INFO system. Preparation of 
Invetory Map of Landsiide Deposits Analysis of Landslide Deposits 
derived from aerial photography(1987.5) 
   
Fig.1 Inventory map of landslide deposits Fig.2 Isopleth map of landslide deposits 
(scale 1:10,000) 
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