• Journal of Environmental Science International
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• v.18 no.11
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• pp.1189-1197
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• 2009

The purpose of this research was develop tailored landslide hazard assessment table (LHAT) in Gyeongsangbuk-do Province and propose building strategies on environmental information system to estimate landslide hazard area according to LHAT. To accomplish this purpose, this research investigated factors occurring landslide at 172 landslide occurred sites in 23 city and county of Gyeongsangbuk-do Province and analyzed what factors effected landslide occurrence quantity using the multiple statistics of quantification method(I). The results of analysis, factors affecting landslide occurrence quantity were shown in order of slope position, slope length, bedrock, aspect, forest age, slope form and slope. And results of the development of LHAT for predict mapping of landslide-susceptible area in Gyeongsangbuk-do Province, total score range was divided that 107 under is stable area(IV class), 107~176 is area with little susceptibility to landslide(III class), 177~246 is area with moderate susceptibility to landslide(II class), above 247 area with severe susceptibility to landslide(I class). According to LHAT, this research built landslide attribute database and made 7 digital theme maps at mountainous area located in Goryeong Gun, Seongju-Gun, and Kimcheon-City. The results of prediction on degree of landslide hazard using environmental information system, area with little susceptibility to landslide(III class) occupied 65.56% and severe susceptibility to landslide(I class) occupied 0.51%.

• Journal of the Earthquake Engineering Society of Korea
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• v.14 no.1
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• pp.35-42
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• 2010

The best estimate Gutenberg-Richter b-value of the Korean Peninsula was estimated through an expert panel assigned to evaluate the currently available study results. The panel's assessment yielded that the Gutenberg-Richter b-value was relatively constant over the Korean Peninsula and was independent of seismic zones with an average value of 0.96. Also, the currently most reliable four seismotechtonic structural maps were produced. The effects on the seismic hazard were analyzed by applying the results to the Shinwuljin Units 1&2 NPP site. As a result, the mean hazard level at 0.2g was decreased by about 70-80% (on the order of 0.6-0.7), and the uncertainty band at 0.2g for the reliability band of 15%-85% was significantly reduced. It was proposed, for conservatism, to use b=0.95 over all seismic zones for seismic hazard analysis in the future.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1A
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• pp.155-162
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• 2006

This study presents the seismic risk assesment for an extradosed bridge with seismic isolators of lead rubber bearings(LRB). First, the seismic vulnerability of a structure and then the seismic hazard of the site are evaluated using earthquake data set and seismic hazard map in Korea, and then the seismic risk of the structure is assessed. The nonlinear seismic analyses are carried out to consider plastic hinges of bridge columns and nonlinear characteristics of soil foundation. The ductility demand is adopted to describe the nonlinear behavior of a column, and the moment-curvature curve of a column is assumed to be bilinear hysterestic. The fragility curves are represented as a log-normal distribution function for column damage, movement of superstructure, and cable yielding. And seismic hazard is estimated using the available seismic hazard maps. The results show that the effectiveness of the seismic isolators for the columns is more noticeable than those for cables and girders, in seismic isolated extradosed bridges under earthquakes.

• Journal of the Korean GEO-environmental Society
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• v.16 no.1
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• pp.17-27
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• 2015

Recently, Korean government has tried out to set up earthquake hazards prevention system. In the system, several geotechnical hazard maps including liquefaction hazard map and landslide hazard map for the whole country have drawn to consider the domestic seismic characteristics. To draw the macro liquefaction hazard map, big data of site investigations in metropolitan areas and provincial areas has to be verified for its application. In this research, we carried out site response analyses using 522 borehole site investigation data in S city during a desirable earthquake. The soil classification was separately compared to shear wave velocity considering the uncertainty of site investigation data. Probability distribution and statistical analysis for the results of site response analyses was applied to the feasibility study. Finally, we suggest a new site amplification coefficient, hereby presented with the similar results of liquefaction hazard mapping using the calculated liquefaction potential index by the site response analyses. Above-mentioned study will be expected to help to follow research and draw liquefaction hazard map in moderate seismic region.

• Geophysics and Geophysical Exploration
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• v.13 no.3
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• pp.295-300
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• 2010

Recently, many tsunamis triggered by impulsive undersea ground motions occurred in subduction zones around the Pacific Ocean area including the East Sea surrounded by Korea, Japan and Russia. The wave height of a tsunami may be in the order of several meters, while the wavelength can be up to 1,000 km in the ocean, where the average water depth is about 4 km. A tsunami could cause a severe coastal flooding and property damage not only at neighboring countries but also at distant countries. A fundamental and economic way to mitigate unusual tsunami attacks is to construct tsunami hazard maps along coastal areas vulnerable to tsunami flooding. These maps should be developed based on the historical tsunami events and projected scenarios. The map could be used to make evacuation plans in the event of a real tsunami assault.

• The Journal of Engineering Geology
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• v.4 no.3
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• pp.321-331
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• 1994

Environmental geologic maps were produced on the cheong-Ju area using GIS technique. They are GIS maps on land management and regional land use planning. In the last year, the model of environmental geologic map was established, and the digital database was constructed by environmental and geotechnical data collected form various sources. The special maps for environmental geologic study were also pnoduced ; landslide hazard and risk map, cut & fill map, actual run-off map and engineering geological map. The maps are secondary models (sub-model) in order to create final environmental geologic map. Finally, Environmental Geologic Unit(EGU) was evaluated for regional land use planning and land management by EGIS(Environmental Geologic Inforafion System). This unit is very important in order to assess environmental geologic impact on large construction works and detailed road design etc.

• Journal of Korean Society of Rural Planning
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• v.11 no.2 s.27
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• pp.9-19
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• 2005

The purpose of this study is to analyze the potential soil loss and hazard zone by the Revised Universal Soil Loss Equation(RUSLE) for preservation and management of land resources which is the base of ecosystem, and to grasp the relationship between RUSLE factors in the Nakdong River Basin. All thematic maps used in RUSLE are constructed through GIS and spatial analysis method derived from digital topographic maps, detailed soil maps, land-cover maps, and mean annual precipitation of 30 years collected respectively from National Geographic Information Institute, National Institute of Agricultural Science and Technology, and Ministry of Environment. The slope length of LS-factor that takes much times by the study area's wideness was calculated automatically through AML(Arc Macro Language) program developed by Van Remortel et al.(2001, 2003). The results are as follows; First, according to the soil loss estimation by the RUSLE, it shows that approximately 82% of the study area have relatively lower possibility of soil loss which is the 1 ton/ha in annual soil loss. While, 9.4% ($2,228km^2$) needed intensive and continuous management for soil loss. Because the amount of their annual soil loss was greater than 10 ton/ha that is optimum level suggested by Morgan(1995). For these areas, the author believe that a new approach which can minimize environmental impacts from soil loss through improvement of cultivation process and buffer forest zone should be applied. Second, according to the relationship between the RUSLE factors, topographical(LS-factor) and cover management(C-factor) conditions have a lot of influence on soil loss in case of the Nakdong River Basin. However, because of RUSLE factor's influence that affect to soil loss might be different based on the variety of spatial hierarchy and extent, it is necessary to analyze and evaluate factor's relationship in terms of spatial hierarchy and extent through field observations and further studies.

• Journal of the Korean Geosynthetics Society
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• v.12 no.2
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• pp.67-74
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• 2013

In this study, the prediction of slope hazard probability was performed to the study area located in Hadae-ri, Woochun-myeon, Hoengsung-gun, Gangwon Province around Youngdong express way using the computer program SHAPP ver 1.0 developed by a decision tree model. The soil samples were collected at total 10 points, and soil tests were performed to measure soil properties. The thematic maps of soil properties such as coefficient of permeability and void ratio were made on the basis of soil test results. The slope angle analysis of topography was performed using a digital map. As the prediction result of slope hazard probability, 2,120 cells among total 27,776 cells were predicted to be in the event of slope hazards. Therefore, the predicted area of occurring slope hazards may be $53,000m^2$ because the analyzed cell size was $5m{\times}5m$.

• The Journal of Engineering Geology
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• v.25 no.4
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• pp.449-458
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• 2015

The compilation of a flood hazard map is an efficient technique in managing areas at risk of flooding in the case of a dam-break. A scenario-based numerical modeling approach is commonly used to compile a flood hazard map related to dam-break and to determine the model parameters that capture peak discharge, including breach formation and progress, which are important in the modeling method. This approach might be considered less reliable if an existing model is used without local validation. In this study, a dam-break model is linked to a routing model to identify flood-risk areas in the case of failure of the Sandae Reservoir Gyeongju, Gyeongbuk. Model parameters are extracted from a DEM, and maps of land use and soil texture. The simulation results are compared with on-site investigations in terms of inundation and depth. The model reproduces the inundation zone with reasonable accuracy.

• Journal of the Korean Geotechnical Society
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• v.38 no.1
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• pp.5-15
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• 2022

Due to the Pohang earthquakes in 2017, concerns are increasing that Korea is no longer safe from liquefaction, and needs the research to take proper measures for liquefaction. Liquefaction is defined as the loss of shear strength of the ground. In order to solve this problem, many studies, such as composing a liquefaction hazard map using Liquefaction Potential Index (LPI), have been conducted. However, domestic researches on the comparative analysis of liquefaction prediction results are not sufficient. Therefore, in this study, liquefaction hazard maps were composed using the standard penetration test results, shear wave velocity values, and cone penetration test results. After that, the precision was determined by comparing the calculated LPI using the geotechnical information and predicted LPI via spatial interpolation target. Based on the analysis results, the predicted LPI value using geotechnical information is more precise than using calculated LPI value.