• Title/Summary/Keyword: slope vulnerable area

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A Study on Urban Flood Vulnerability Assessment Considering Social Impact (사회적 평가 지표를 반영한 도시 홍수취약성 평가)

  • Lee, Gyu Min;Choi, Jin Won;Jun, Kyung Soo
    • Land and Housing Review
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    • v.11 no.1
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    • pp.109-116
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    • 2020
  • This study aims to establish an approach to assess urban flood vulnerability by identifying social characteristics such as the road transportation and the vulnerable groups. Assessment procedures comprise three steps as: (1) composing the assessment criteria to reflect the urban characteristics; (2) calculating the weight; and (3) evaluating the vulnerability. The criteria were adopted by Delphi survey technique. Four criteria as land cover, residents, vulnerable areas, and disaster response were adopted in the current study. To determine the weight set of criteria, subjective and objective methods were combined. The weight set was determined using the combined method which reflects the Delphi method and Entropy analysis. In the process of data-based construction, GIS tools wwere used to extract administrative unit materials such as land cover, road status, and slope. Data on population and other social criteria were collected through the National Statistical Office and the Seoul Metropolitan statistical data. TOPSIS (Technique for Order of Preference by Similarity to Ideal Solution) technique, which uses materials from cell units in order to rank the closest distance to the best case and the farthest distance from the worst case by calculating the distances to the area of assessment, was applied to assess. The study area was the Dorimcheon basin, a flood special treatment area of Seoul city. The results from the current study indicates that the established urban flood vulnerability assessment approach is able to predict the inherent vulnerable factors in urban regions and to propose the area of priority control.

Selecting and Assessing Vulnerable Zones of Snow Damage in Urban Areas - the case of City of Busan (도심의 설해취약지역 선정 및 위험도 평가에 관한 연구 - 부산광역시 지형적 특성을 중심으로 -)

  • Koo, Yoo Seung;Lee, Sung Ho;Jung, Juchul
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.33 no.3
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    • pp.1077-1086
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    • 2013
  • Recent huge losses of both life and property have occurred by unexpected natural disasters. We studied snow damages, an important natural disaster issue because it happens more frequently in recent years. This study tries to select vulnerable areas of snowfall in advance and then establish climate change adaptation policy for minimizing unexpected snowfall damage. Busan, where is our study area, has hilly in downtown areas so that topography characteristics of the roads such as slope, elevation and aspect are vulnerable to snowfall. The sudden snowfall in Busan causes traffic jam and causes some schools in hilly to close some schools. At this moment, the adaptation policy has to be established for infrastructure (such as roads) in advance, because prediction of anomaly climate due to global warming is so difficult beside the damage of natural disaster is huge. Therefore, the purpose of this study is contribute to selecting and assessing vulnerable zones of snow damage focusing topography characteristics of the roads and then evaluating the degree of risk of vulnerable zones.

Drainage Control and Prediction of Slope Stability by GIS-based Hydrological Modeling at the Large Scale Open Pit Mine (GIS에 의한 대규모 노천광에서의 배수처리 및 사면안정 예측)

  • SunWoo, Choon;Choi, Yo-Soon;Park, Hyeong-Dong;Jung, Yong-Bok
    • Tunnel and Underground Space
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    • v.17 no.5
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    • pp.360-371
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    • 2007
  • This paper presents an application of drainage control and slope stability by GIS-based hydrological modeling to control the surface water from an operational point of view. This study was carried out on a region of Pasir open-pit coal mine, Indonesia. A detailed topographical survey was performed at the study area to generate a reliable DEM (Digital Elevation Model). Hydrology tools implemented in ArcGIS 9.1 were used to extract the characteristics of drainage system such as flow direction, flow accumulation and catchment area from DEM. The results of hydrological modeling and spatial analysis showed that current arrangement of pumping facility is not suitable and some vulnerable places to erosion exist on the bench face due to concentrated surface runoff. Finally, some practical measures were suggested to optimize the design of drainage system and to monitor the slope stability by the surface water management at the study region during heavy rainfall.

Soil Characteristics according to the Geological Condition of Soil Slopes in Landslide Area (산사태지역 토층사면의 지질조건별 토질특성)

  • Kim, Kyeong-Su
    • The Journal of Engineering Geology
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    • v.16 no.4 s.50
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    • pp.359-371
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    • 2006
  • In this study, the soil characteristics are analyzed using the result of various soil tests as an object of the soil layer of natural slopes in landslides areas composed with gneiss, granite, and the tertiary sedimentary rock. To investigate the soil characteristics according to landslide and non landslide areas, soils are sampled from Jangheung, Sangju and Pohang. The landslides at three areas are occurred due to heavy rainfall in same time. The geology of Jangheung area, Sangju area and Pohang area is gneiss, granite, and the tertiary sedimentary rock, respectively. On the basis of the landslide data and the result of soil test, the soil characteristics at the landslide area and the differentiation between landslide area and non landslide area are analyzed. However soil characteristics have a little differentiation to geological condition, the uniformity coefficient and the coefficient of gradation of soils at the landslide area is larger than those of soils at the non landslide area. Also, the proportion of fine particle of soils at the landslide area is higher. The plastic limit of soils sampled from the granite and the sedimentary rock regions is larger than that sampled from the gneiss region. However the liquid limit is irrelevant to the geological condition. Also, the consistency of soils at the landslide area is smaller. The natural moisture content of soils in the sedimentary rock regions is larger than that of the granite and gneiss. It is mainly influenced by mineral composition, soil layer structure, weathering condition, and so on. The soils sampled from landslide area have higher porosity and lower density than those from non landslide area. It means that the soils of landslide area have poor particle size distribution and loose density. Therefore, the terrain slope with poor distribution and loose density is vulnerable to occur in landslides. Also, landslides are occurred in the terrain slope with high permeability. The permeability is mainly influenced by the soil characteristics such as particle size distribution, porosity, particle structure, and the geological origins such as weathering, sedimentary environment. Meanwhile, the shear strength of soils is little difference according to the geological condition. But, the internal friction angle of soils sampled from the landslide area is lower than that of soils from the non landslide area. Therefore, the terrain slope with low internal friction angle is more vulnerable to the landslide.

A Study of Damage District Forecast by Combine Topograph Modeling of Insular Areas Using GIS

  • Choi, Byoung Gil;Na, Young Woo;Ahn, Soon Myoung
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.35 no.2
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    • pp.113-122
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    • 2017
  • Natural disasters caused by climate change are increasing globally. There are few studies on the quantitative analysis methods for predicting damages in the island area due to sea level rise. Therefore, it is necessary to study the damage prediction analysis method using the GIS which can quantitatively analyze. In this paper, we analyze the cause and status of sea level rise, quantify the vulnerability index, establish an integrated terrestrial modeling method of the ocean and land, and establish a method of analyzing the damage area and damage scale due to sea level rise using GIS and the method of making the damage prediction figure was studied. In order to extract the other affected areas to sea level rise are apart of the terrain model is generated by one requires a terrain modeling of target areas are offshore and vertical reference system differences in land, found the need for correction by a tidal observations and geoid model there was. Grading of terrain, coastline erosion rate, coastal slope, sea level rise rate, and even average by vulnerable factors due to sea level rise indicates that quantitative damage prediction is possible due to sea level rise in the island area. In the case of vulnerable areas extracted by GIS, residential areas and living areas are concentrated on the coastal area due to the nature of the book area, and field survey shows that coastal changes and erosion are caused by sea level rise or tsunami.

The Spatial Location Analysis of Disaster Evacuation Shelter for Considering Resistance of Road Slope and Difference of Walking Speed by Age - Case Study of Seoul, Korea (도로경사와 연령별 보행속도 차이를 고려한 자연재난 대피소의 입지분석 - 서울시 사례분석)

  • Lee, So Hee;Goo, Sin Hoi;Chun, Young Woo;Park, Young Jin
    • Journal of Korean Society for Geospatial Information Science
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    • v.23 no.2
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    • pp.69-77
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    • 2015
  • In Korea, local governments have decided the location of shelters as part of their disaster planning. However, no quantitative standards, such as assuming different hazard and shelter types, shelters' capacity, are specified in that planning. To propose the direction of disaster evacuation policy, first of all, the current state of shelters' location and evacuation area is needed to be analyzed. In addition, considering topographical condition such as road slope and physical strength by age are important factors to measure optimal evacuation route. The purpose is to suggest a new methodology of estimating optimal evacuation route considering resistance of road slope and difference of walking speed by age. Moreover, as a case study of Seoul, Korea, using coverage analysis of GIS analysis tool, the accessible area (or vulnerable area) to the shelters is evaluated based on the spatial distribution of disaster evacuation shelters and their accommodation capacity, according to evacuation time within 7.5, 15 and 30 minutes. The main results are summarized as follows: 1) The average area of disaster evacuation shelter per person is calculated as 0.45 square meters. Considering that the minimum shelters' area per person is 1 square meters, only 45% of people in Seoul can be accommodated. 2) The ratio of inhabitants who live in accessible area within 7.5 minutes presents only 33% of all. Furthermore, the ratio of inhabitants by age group of 5~9 or over 65 years old shows significantly lower percentage in comparison with 15~49 years old people.

The Evaluation on the Prediction Ratio of Landslide Hazard Area based on Geospatial Information (공간정보 기반 산사태 발생지역 예측비율 평가)

  • Lee, Geun-Sang;Lee, Ho-Jun;Go, Sin-Young;Cho, Gi-Sung
    • Journal of Cadastre & Land InformatiX
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    • v.44 no.2
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    • pp.113-124
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    • 2014
  • Recently landslide occurs frequently by heavy rainfall, therefore there area many studies to analyze the vulnerable district of landslide and forecast the occurrence of landslide. This study analyzed soil characteristics in the occurrence district of landslide and the occurrence possibility of landslide ranked high in well draining soil as the result of frequency ratio according to the characteristics of drainage. Also as the result of frequency ratio of slope derived from DEM data, the occurrence possibility of landslide ranked high in slope range of $20{\sim}40^{\circ}$. And Also as the result of frequency ratio of aspect by geospatial analysis, the occurrence possibility of landslide ranked high in north aspect. Also, it is possible to evaluate the vulnerability of landslide by overlapping frequency ratio of the drainage of soil, slope and aspect. And future prediction ratio of landslide occurrence can be evaluated by performing the analysis and validation process respectively on the subject of the occurrence district of landslide.

Geomorphic-characteristics of debris flow induced by typhoon "RUSA" in 2002 using Shalstab Model and Remote Sensing: case study in Macheon region near Jiri-Mountain (원격탐사와 수치 모형을 이용한 2002년 태풍 "루사"에 의해 발생한 토석류 발생지점특성: 지리산 마천면 지역을 사례로)

  • Kim, Minseok;Kim, Jin Kwan;Cho, Youngchan;Kim, Sukwoo
    • Journal of The Geomorphological Association of Korea
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    • v.18 no.4
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    • pp.193-202
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    • 2011
  • Kompsat EOC-1 imagery, high resolution air-photo imagery and Shalstab model were used to analyze the geomorphic characteristics of the place of debris flow occurred by typhon "RUSA" in 2002, Macheon-Myen, Gyeongsang prefecture, Republic of Korea. On gully-head over 35 degree of slope angle, almost debris flow started, where slope angle is more than internal friction angle. The result simulated by Shalstab model presented larger vulnerable area to debris flow than the area where debris flow really occurred, this error would be attributed to the assumption for steady-state condition with full saturated surface. To predict the debris flow accurately, further study for rainfall and soil water flow will be needed.

Watershed Scale Management Techniques of the Pollutants from Small Scale Livestock Ranches - Buffer Zone Selection for Natural Purification - (농촌 소유역 축산폐수의 유역관리기법 개발 - 자연정화처리를 위한 완충대 적지분석 -)

  • Kim, Seong-Joon;Lee, Nam-Ho;Yoon, Kwang-Sik;Hong, Seong-Gu;Lee, Yun-Ah
    • Journal of Korean Society of Rural Planning
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    • v.6 no.2 s.12
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    • pp.43-49
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    • 2000
  • Buffer zone selection technique for natural purification of livestock wastewater within a small agricultural watershed was developed using Geographic Information Systems. The technique was applied to $4.12\;km^2$ watershed located in Gosan-myun, Ansung-gun which have 20 livestock farmhouses. As a necessary data for selecting process, feedlot site map, digital Elevation Model (DEM), stream network, soil and land use map were prepared. By using these data, wastewater moving-path tracing program from each feedlot to the stream was developed to get the basic topographic factors; average slope through the paths, distance to the nearest stream and watershed outlet. To identify the vulnerable feedlots for storm event, the grid-based storm runoff model (Kim, 1998; Kim et al., 1998) was adopted. The result helps to narrow down the suitable area of buffer zone, and finally by using subjective but persuasive conditions related to elevation, slope and land use, the suitable buffer zones were selected.

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An Exploratory Study on the Analysis of Characteristics of Pedestrian Accident Vulnerable Points using Road View: Focusing on Sasang-gu, Busan (로드뷰를 활용한 보행자 사고 취약 지점 특징 분석 탐색적 연구: 부산광역시 사상구를 중심으로)

  • Dong Kyu Lee;Jae Seon Kim;Kyung Soo Pyo;Min Kim
    • Journal of the Society of Disaster Information
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    • v.20 no.2
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    • pp.351-368
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    • 2024
  • Purpose: In general, traffic accidents occur sporadically, so there are various limitations in terms of time and cost when conducting field investigations to prepare prevention and prevention measures. In particular, with the transition to a non-face-to-face society after the COVID-19, there is a greater need to prepare a replacement for field surveys. Therefore, in this study, Roadview provided by various websites was used as an alternative to field surveys in Sasang-gu, Busan City. The possibility was evaluated. Method: The research method was to extract vulnerable points for traffic accidents that occurred between 2016 and 22 and analyze road views based on the field survey evaluation items provided in the Traffic Safety Diagnosis Guidelines. Result: The main result was that Sasang-gu was most vulnerable to accidents involving elderly pedestrians at Sasang-ro, Daedong-ro, and Hakjang-ro. As a result of a detailed analysis of vulnerable points through Road View, Sasang-ro needed control of commercial vehicles and protection of the transportation vulnerable in the market commercial area. Daedong-ro was vulnerable to illegal on-street parking and slope merging sections, and Hakjang-ro was vulnerable to roads that were prone to speeding. When evaluating the possibility of replacing Roadview's field survey based on the results of this analysis, Roadview was able to effectively evaluate most items, such as separation of sidewalks and the location and spacing of safety facilities. However, there were limitations in items such as actual measurement performance. Conclusion: In other words, the road view can replace most field surveys, and the actual measurement evaluation items can be judged to be useful as auxiliary data, resulting in time and cost savings and high efficiency.