• Title/Summary/Keyword: aspect of slope

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Topographic Analysis of Landslides in Umyeonsan (우면산 산사태 발생 지점의 지형분석)

  • Ko, Suk Min;Lee, Seung Woo;Yune, Chan-Young;Kim, Gihong
    • Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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    • v.32 no.1
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    • pp.55-62
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    • 2014
  • In this study, we investigated the landslides area which occurred in Umyeonsan in 2011 and collected landslide location data. Using this field data with aerial photos and LiDAR data which is obtained before and after disaster event, we analyzed the landslide occurrence frequency per unit area about various topographic characteristics. In case of slope, we compared two kind of slopes which are calculated with Neighborhood algorithm and maximum slope algorithm. Also we used aspect, elevation, profile curvature and planform curvature in topographic analysis of landslide occurrence locations. As a result, the region of which maximum slope is $40^{\circ}-45^{\circ}$ is relatively hazardous in landslide. If the perpendicular surface to the direction of the maximum slope is concave, it is more hazardous than other case.

Characteristics of Water Relation Parameters for Pinus densiflora at Different Aspects in Central South Korea (입지 유형에 따른 중부지방 소나무의 수분생리 특성)

  • 신만용;정동준;신창섭
    • Korean Journal of Agricultural and Forest Meteorology
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    • v.6 no.1
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    • pp.18-23
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    • 2004
  • This study was conducted to provide a national forest management method for natural Pinus densiflora forest stands in central South Korea based on growth characteristics and water relations. Average stand volume per hectare was 259.3㎥ in the pine study site. Basal area, volume, annual mean increment and periodic annual increment of DBH for 10 years at each slope aspect appeared to decrease as the aspect shifts from north to south. Stems per hectare showed the lowest value at the northern aspect. Maximum water potentials measured between 12 and 14 o'clock were analyzed by aspect and elevation. Water potential of pine decreased as the aspect changed from north to south, and water potential increased at lower elevations. Soil water content for the pine stands tended to decrease as the aspect shifted from north to south. Water potential and soil moisture content were highly correlated. Soil water deficits indicate that pines have a higher moisture requirement on the ridge and the southern aspect.

Analysis of the Geomorphological Environments of High-Density Residential Zone in Bronze Age around Asan City, Central Korea - A Case Study of Yongdoocheon and Onyangcheon Basin - (충남 아산의 청동기 시대 주거지 밀집 구역의 지형환경 분석 - 용두천과 온양천 유역을 사례로 -)

  • Park, Ji-Hoon;Park, Jong-Chul
    • Journal of the Korean Association of Geographic Information Studies
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    • v.14 no.3
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    • pp.110-125
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    • 2011
  • A number of the Bronze Age dwelling sites have been found and excavated in the Yoodoocheon, Onyangcheon and Baekseokdong basins. Two basins are located near Asan and Onyan in the Chungnam Province of South Korea. Baekseokdong is located in Cheonan, Chungnam. 207 dwelling sites are concentrated around the area of $1.3km^2$ in the Baekseokdong. 177 dwelling sites are sparse and distributed over the area of $1.3km^2$ in the Yongdoocheon and Onyangcheon basins. Most of the Bronze Age dwelling sites in those areas located on the hill. The hills have similar geomorphological environments except for slight differences in geological faces. This study analyzes geomorphological environments of the high-density residential zone of the Bronze Age in the Yoodoocheon and the Onyangcheon basins, and then compares them with the results in Baekseokdong. Study results show that high-density residential zone consists mainly of specific micro-landforms such as the Crest slope, the Crest flat and the Upper side slope, and southeast-facing aspect. A lot of Gentle slope lands were distributed in terms of terrain slope but it is far from specific geomorphological environments. This is not weighted in specific value. Our results show that the geomorphological characteristic derived from this study is major considerations to develop dwelling sites in the Bronze Age. This can be useful to discover the possible dwelling sites over other Chungnam hill regions.

Slope Stability and Development of Debris Flow Deposit in the Ulleung Basin, East Sea (동해 울릉분지의 사면안정성 및 쇄설류 퇴적체의 발달)

  • Lee, Sun-Jong;Lee, Jeong-Min;Yoo, Dong-Geun;Lee, Go-Eun;Park, Soo-Chul
    • Economic and Environmental Geology
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    • v.50 no.2
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    • pp.129-143
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    • 2017
  • The shallow sediments in the southwestern Ulleung Basin consist of mass flow deposits such as slide/slump and debris flow deposits (DFD), caused by slope failure. These sediments are proven to be important in studying geological disaster and stability of the seafloor. In this paper, we analysised the flow accumulation and slope failure susceptibility of the Ulleung Basin on the basis of multi-beam data, collected in this area. We also studied the distribution pattern and the seismic characteristics of the DFD in the uppermost layer of the Ulleung Basin on the basis of seismic data. The slope susceptibility was calculated as the frequency ratio of each factors including slope, aspect, curvature and stream power index (SPI), which causes the slope failure. These results indicate that the slope failure is frequently to occur in the southern and western continental slope of the Ulleung Basin. The sediment flow (mass flow) caused by the slope failure converges to the north and northwest of the Ulleung Basin. According to the seismic characteristics, the uppermost layer in study area can be divided into four sedimentary unit. These sedimentary units develop from the south and southwest to the north and northwest in association with slope susceptibility and flow accumulation.

Landslide Susceptibility Evaluation in Yanbian Region

  • Liu, Xiuxuan;Quan, Hechun;Moon, Hongduk;Jin, Guangri
    • Journal of the Korean GEO-environmental Society
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    • v.18 no.2
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    • pp.21-27
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    • 2017
  • In order to evaluate landslide susceptibility in Yanbian region, this study analyzed 7 factors related to landslide occurrence, such as soil, geology, land use, slope, slope aspect, fault and river by Analytic Hierarchy Process (AHP), and calculated the weights of these 7 hazard-induced factors, determined the internal weights and the relative weights between various factors. According to these weights, combining the Remote Sensing technology (RS) with Geographic Information System technology (GIS), the selected area was evaluated by using GIS raster data analysis function, then landslide susceptibility chart was mapped out. The comprehensive analysis of AHP and GIS showed that there has unstable area with the potential risk of sliding in the research area. The result of landslide susceptibility agrees well with the historical landslides, which proves the accuracy of adopted methods and hazard-induced factors.

Case Study of the Early Stage Vegetation Recovery with Soil Property in the Roadside Slopes of the Expressway (고속도로 비탈면 녹화공법 시험시공지의 토질조건별 초기 녹화효과 사례연구)

  • Jeman Lee;Kyung-Hoon Kim;Gi-Seong Jeon;Sangjun Im
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.26 no.2
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    • pp.47-59
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    • 2023
  • This study investigated and analyzed the effects of vegetation on the roadside slopes at the expressway construction sites in order to evaluate the vegetation recovery regarding soil type and revegetation technique. We selected two study sites with an area of 1,000 m2 located in the construction sites of the Korea Expressway Corporation, named Hwado-Yangpyeong Expressway Section 3 and Saemangeum-Jeonju Expressway Section 7. The revegetation was monitored in three plot groups (earth, soft rock, and hard rock slopes), and scored based on the guideline of the Ministry of Land, Transport and Maritime Affairs. The revegatation was generally lower in the Hwado-Yangpyeong site than that of the Saemangeum-Jeonju site. The field monitoring indicated that the revegetation varied with slope aspect and environmental characteristics between plots. the Saemangeum-Jeonju site showed a high overall evaluation score, but there was a slight difference in the score for each plot. This seems to be due to the differences in geographical conditions, construction methods, and site environment between two sites. This study can provide basic information to understand the short-term effects of revegetation techniques in the roadside slopes.

A Prediction Model of Transverse Bed Slope in Meandering Rivers (사행하천(蛇行河川)의 횡방향(橫方向) 하상경사(河床傾斜)의 예측모형(豫測模型))

  • Hong, Chang Sun;Chung, Yong Tai
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.11 no.4
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    • pp.81-89
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    • 1991
  • An interesting property of meandering river patterns is that they slowly deform, as bank erosion on one side of a channel and deposition on the other side result in the location of the channel. In this study we used a sine-generated meander pattern proposed by Langbein and Leopold(1966) to develop a solution of a linear, second-order differential equation of transverse bed slope(bed topography) proposed by Odgaard(1986). A new model for transverse bed slope(bed topography), that accounts for the phase lag and the influence of the width to depth aspect ratio, was developed in this study and compared with results of field measurements.

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Changing of Vegetation Coverage through Elapsed Years on Cutting Slope in Forest Roads (시간경과에 따른 임도 절토비탈면의 식생피복도 변화)

  • Jeon, Kwon-Seok;Ma, Ho-Seop
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.7 no.3
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    • pp.14-25
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    • 2004
  • The purpose of this study was investigated to the change of vegetation coverage by elapsed years on the cut slope of forest road in Jinju-si. The results obtained could be summarized as follows; The plant coverage on the cut slope of forest road was decreased hastily in first and second year after seeding. The plant coverage on the cut slope of forest road was increased as growth of seed-sprayed from third year. But the plants were began to competition with between sprayed seeds and invaded plants from third to fifth year after seed-spray. The numbers of invading plants were gradually increased as 581 individuals from sixth year after seed-spray. The cut slopes of the forest roads turned to a good site condition for growing of invasion plants. And also the total coverage on cut slope of forest roads by invading of surrounding plants was increased more. It showed that plant invasion on cut-slopes of forest roads would be mostly influenced by surrounding plants. The number of surrounding plants on the cut-slopes of forest roads was 59 species, and the number of invading plants showed 65 species. The invading species were high in order of Boehmeria tricuspis, Oplismens undulatifolius, Miscanthus sinensis var. purpurascens, Erechtites hieracifolia and Artemisia princeps var. Orientalis In the stepwise regression analysis, main factors affecting the coverage of vegetation on the cut-slopes of forest road showed in order of elapsed years, gravel contents(30~50%), middle, sandy loam, sandy clay-loam, soil hardness, aspect(NS), concave(凹) type and gravel contents(15~30%).

Effects of Forest Environmental Factors and Forest Road Structures on the Stability of Forest Road in Granite Areas (화강암지역의 산림환경 및 도로구조인자가 임도의 안정성에 미치는 영향)

  • Yim, Byung-Jun;Ma, Ho-Seop
    • Journal of the Korean Society of Environmental Restoration Technology
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    • v.2 no.3
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    • pp.83-92
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    • 1999
  • To investigate the influence of forest road characteristics and site conditions on the stability of forest-road in granite area, four forest roads had been selected in Kyongbuk regions. The total of 13 road characteristic variables were evaluated by the discriminant analysis. The factors influencing the stability of forest road were bed rock, slope length, coverage, hardness, side-ditch erosion and road width. But aspect and soil texture were not significant for the stability in this area. In the correlation between forest environment and road structure, hardness and bed rock was highly significant in stability group, and coverage and side-ditch erosion was highly significant in instability group. 75 of 175 segments were instable whereas the others were stable. The centroids value by discriminant function in the stability and instability were estimated to 3.0585 and -1.9116, respectively. The stability criterion of forest road was discriminated from the centroids value of the each group. The main factors contributing the stability of forest road were significant in order of side-ditch erosion, coverage, soil texture, elevation, gradient, slope length and construction year. The prediction rate of discriminant function for stability evaluation of forest road was as high as 97.44%. In conclusion, the forest road structure factors such as length, coverage and slope gradient were controlled by construction techniques. If the factors like those should be considered in design, construction and forest road management, the stability of forest road may increase more. And also, it is necessary to take slope protection measures like small terraces and retaining walls for stability of cut slope.

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A Study on the Three Dimensional Road Design Technique Based on GIS Technique (GIS를 이용한 3차원도로시뮬레이션에 관한 연구)

  • Gwon, Hyeok Chun;Lee, Byeong Geol
    • Journal of Environmental Science International
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    • v.13 no.6
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    • pp.489-495
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    • 2004
  • The purpose of this research is to apply GIS(Geographic Information System) for the road simulation and find some benefits analysis for the design processes. The northern Jeju island was selected as a case study. The 1/5,000 digital map and GIS technique were used for optimum road design of the island based on Arc View software. Using this software we can get an overlay map by combination of hill shade map, slope map, aspect map, and building buffer map. Based on the overlay map, we designed the optimum road line and performed three dimensional simulation. From the results, we found that the developed three dimensional road simulation technique using GIS technique that was very useful tool to estimate the reasonable road design before the real road construction works.