• Title/Summary/Keyword: Rock Slope

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Geochemical Approach to Define the Fracture Bone Affected by the Ubo Fault at the Northern Part of the Hwabuk Dam (화북댐 상류지역을 통과하는 우보단층 파쇄대 영향분석을 위한 지화학적 접근)

  • Kwon Yong Wan
    • The Journal of the Petrological Society of Korea
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    • v.13 no.4
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    • pp.191-200
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    • 2004
  • The Ubo fault Bone, which cross over the northwestern to southeastern direction at the Hwabuk damsite in Hakseongri, Gunwigun, Gyeongsangbukdo Province, has length about 20km. The Ubo fault zone in this area is segmented to several small faults and makes a gentle slope and hill along the right side of the drainage in the Hwabuk dam. In the storage area of Hwabuk dam, 2 pairs of faults occur and the width of fracture zones are about 2m. To define the fracture Bone using the geochemical data, the samples were collected at 0.5m, 1m, 2m, 4m, 8m, 16m and 32m apart from the center of the main fracture Bone toward north and south, respectively, and analyzed for major elements and mineral content Approaching the fracture Bone, Fe$_2$O$_3$, MgO, K$_2$O, quartz, muscovite and chlorite are increasing and Na$_2$O, CaO, plagioclase and biotite are decreasing, respectively. Based on the rock chemistry and mineral content, the range of the main fracture zone affected by the Ubo fault at Hakseongri is 2m width in total, the secondary deformed zone is 8m width in total. Finally the maximum affected range by the Ubo fault is inferred to 16m width in total.

Analysis of Ancient Document and Establishment of Petrological Database for Presumption of Stone Source Area of the Seoul City Wall, Korea (한양도성 석재공급지 추정을 위한 고문헌 분석 및 암석학적 데이터베이스 구축)

  • Jo, Young Hoon;Lee, Chan Hee
    • The Journal of the Petrological Society of Korea
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    • v.24 no.3
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    • pp.193-207
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    • 2015
  • This study analyzed ancient documents and established petrological database through extensive field investigation of provenance sites to presume stone source areas of the Seoul City Wall. By summarizing the ancient documents, the rampart stone was mostly supplied from a stony mountain adjacent to the City Wall in the early Joseon period, whereas the stone was provided from fixed quarry outside the City Wall in the late Joseon period. As a result of the petrological investigation based on quarries recorded in the ancient documents, pinkish granite and leucogranite were distributed as a whole, and the granitoid rocks are similar in mineralogical compositions and geochemical behavior characteristics. However, the pinkish granite with magnetic-series show that the magnetic susceptibility increased from the north slope of Namsan Mountain to Bulamsan Mountain. The leucogranite with ilmenite-series mainly occurred along the boundary between granite and gneiss from Yongmasan Mountain to Inwangsan Mountain. Consequently, the important petrological indicators for presumption of stone source areas are the rock color and the magnetic susceptibility. In addition to the petrological features, the reliability for provenance interpretation should improve considering stone quantities in the quarries, transportation distance and technical skills.

Syntaxonomical and Synecological Research of Forest Vegetation on Mt. Byeokbang (벽방산 산림식생의 군락분류와 군락생태)

  • Choi, Byoung-Ki;Huh, Man-Kyu;Kim, Seong-Yeol
    • Journal of Life Science
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    • v.25 no.6
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    • pp.646-655
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    • 2015
  • A phytosociological survey carried out using the Z.-M. School’s methodology and system of numerical-classification analyses, this study sought to classify the syntaxa of forest vegetation on Mt. Byeokbang and to collect basic data on the transitional zones of the southern Korean peninsula’s coastal region. The syntaxa were classified into three physiognomic types and nine communities, including (1) evergreen coniferous forests (Eurya japonica-Pinus thunbergii community and Ardisia japonica-Pinus densiflora community), (2) summer-green, broad-leaved forests (Chloranthus japonicus-Quercus serrate community, Syneilesis palmata-Quercus mongolica community, Quercus acutissima community, Carpinus turczaninovii var. coreana community, Fraxinus siebolidiana-Quercus dentate community, and Deutzia glabrata-Lindera erythrocarpa community), and (3) artificial afforestation (Alnus firma afforestation). The Chloranthus japonicus-Quercus serrata community, Syneilesis palmata-Quercus mongolica community, Fraxinus siebolidiana-Quercus dentata community, Carpinus turczaninovii var. coreana, community and Deutzia glabrata-Lindera erythrocarpa community were closely evaluated for national vegetation naturalness. It was confirmed that the Carpinus turczaninovii var. coreana community was endemic to Korea. Most syntaxa were defined as a secondary forestation due to various human activities (e.g., forest fires, logging, digging, climbing, etc.). The results of a canonical-correspondence analysis (CCA) showed that human activities, altitude, humus depth, rock cover ratio, slope, etc. were the main ecological factors determining the classified plant communities’ distribution patterns.

The Analysis of Vegetation Clustering and Stand Structure for Thuja orientalis Forest in Dodong, Daegu (대구 도동측백나무림의 식생군집 분류 및 임분 특성 분석)

  • Park, Byeong-Joo;Kim, Jae-Jin;Lee, Dong-Jin;Joo, Sung-Hyun
    • Journal of Korean Society of Forest Science
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    • v.104 no.4
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    • pp.519-526
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    • 2015
  • This study was investigated to analyze stand structure in Daegu Dodong T.orientalis Forest for conservation Thuja orientalis forest. Results of cluster analysis, it was classified to Quercus variabilis group(A), Quercus variabilis-Quercus mongolica group(B), Pinus densiflora group(C), Thuja orientalis group(D). Charaters of location environments for D group were analyzed that altitude 99.3 m, slope $59^{\circ}$, rock exposure 68.3%, BHA $21.8m^2/ha$ and North West aspects. The MRPP-test, It classified groups, appropriately. Importance value of D group was T. orientalis 85.42, Q. variabilis 1.28, P.densiflora 1.30, Fraxinus rhynchophylla 3.56 etc. DBH classes of D group were expressed inverted-J-shaped curve. H' was resulted in 0.600~0.834, H'max 1.317~1.466, J' 0.456~0.594, D' 0.405~0.544. Indecator species Analysis were conducted that woody plants were 4 taxa, Herbal plants 9 taxa.

A Study on the Distribution Characteristics of Buxus koreana in Kwanaksan Ecological and Scenery Conservation Area (관악산 생태경관보전지역 내 회양목 분포 특성 연구)

  • Lee, Ho-Young;Oh, Choong-Hyeon;Lee, Sang-Jin
    • Korean Journal of Environment and Ecology
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    • v.26 no.1
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    • pp.91-99
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    • 2012
  • The purpose of this study was to find out the vegetation community structure and the distribution characteristics of Buxus koreana through analysis of the topography and soil characteristics in Kwanaksan Ecological and Scenery Conservation Area. To do this twenty two plots as $100m^2$ each were set up and investigated. As a result, the vegetation communities were classified in four groups; Pinus rigida community (I), P. rigida - B. koreana community(II), Quercus mongolica community(III), Quercus acutissima - Quercus serrata community(IV). The distribution characteristics in topography appeared that B. koreana distributed more in valley where soil water and nutrition conditions are good. The drainage condition also influenced the distribution, because the ratio of clay was low in the result of soil texture analysis. B. koreana was distributed in high-pitched slope and the high rock ratio area. According to the soil analysis, the mean soil pH of B. koreana distributed groups(pH 4.79) was higher than that of non-B. koreana distributed groups(pH 4.41). It appeared that B. koreana had tolerance to the barren soil, so the value of exchangeable cations such as $Ca^{2+}$ and $Mg^{2+}$were showed lower than that of the average of Korean forest soil.

A Study on the Characteristics of the Byeolwon (別苑: A Separate Garden Made Away from Living Space) in Palace during the Joseon Dynasty period Illuminated by the Oungak Area at the Rear Garden of Reconstructed Gyeongbokgung Palace (중건 경복궁 후원 오운각(五雲閣) 권역으로 조명한 조선시대 궁궐 별원(別苑)의 특성)

  • Jung, Woo-Jin
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.34 no.3
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    • pp.1-17
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    • 2016
  • The main aim of this study is to provide an overview of the characteristics the Oungak (五雲閣) area on the north of rear garden of Gyeongbokgung Palace which was constructed during the time of king Kojong. This study also consider the aspect of functional elements of Ocryucheon (玉流川) located in Changdeokgung Palace and how the Oungak area was used as a substitute for the Ocryucheon. The Oungak area is the private space of the king. It was built in a natural setting which used existing environment including spring water and the rock carved with inscriptions 'Cheonha-Jaeil-Bokji (天下第一福地). King Kojong tried to replace Ocryucheon with Oungak area which had played a important role of relaxation and leisure for royal family at the Ocryucheon to reconstructed Gyeongbokgung Palace. Despite being away from each other, Oungak area seems quite similar to Ocryucheon area. Oungak area and Ocryucheon have a common conditions of a location and structure of the building. Both constructed on the northernmost part of rear garden, composition of buildings and the design of waterway estimated to function as Curve-Stream Banquet. Oungak area was consisted of Ocryeonjeong (玉蓮亭) Pavilion, Oungak Building, Byeokhwasil (碧華室) Building and Cheonha-Jaeil-Bokji-Cheon (天下第一福地泉) Spring and Streams. Except Byeokhwasil Building, spatial compositions of Oungak area showed pattern that were similar to Ocryucheon area. The area was developed, moreover, to unconventional space that depended on the conditions of topography, slope, water system. First, The Ocryeonjeong Pavilion constructed to view the landscape of Seoul to Namsan Mountain. Second, the peculiar form of Cheonha-Jaeil-Bokji-Cheon Streams is estimated the shape imitated from Curve-Stream Banquet on Ocryuchon. Third, Oungak Building was constructed like a habitable house with Nongsanjeong Building in Ocryucheon. The Oungak area was constructed to improve Gyeongbokgung Palace, Consequently, the Oungak area specially characteristic of Joseon palaces's rear garden.

The Current Methods of Landslide Monitoring Using Observation Sensors for Geologic Property (지질특성 관측용 센서를 이용한 산사태 모니터링 기법 현황)

  • Chae, Byung-Gon;Song, Young-Suk;Choi, Junghae;Kim, Kyeong-Su
    • Journal of Sensor Science and Technology
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    • v.24 no.5
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    • pp.291-298
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    • 2015
  • There are many landslides occurred by typhoons and intense rainfall during the summer seasons in Korea. To predict a landslide triggering it is important to understand mechanisms and potential areas of landslides by the geological approaches. However, recent climate changes make difficult to predict landslide based on only conventional prediction methods. Therefore, the importance of a real-time monitoring of landslide using various sensors is emphasized in recent. Many researchers have studied monitoring techniques of landslides and suggested several monitoring systems which can be applicable to the natural terrain. Most sensors of landslide monitoring measure slope displacement, hydrogeologic properties of soils and rocks, changes of stress in soil and rock fractures, and rainfall amount and intensity. The measured values of each sensor are transmitted to a monitoring server in real-time. The ultimate goal of landslide monitoring is to warn landslide occurrence in advance and to reduce damages induced by landslides. This study introduces the current situation of landslide monitoring techniques in each country.

Geographical Distribution and Ecology in Microhabitats of the Rare Species, Pulsatilla tongkangensis Y.N. Lee et T.C. Lee (희귀종인 동강할미꽃(Pulsatilla tongkangensis Y.N. Lee et T.C. Lee)의 지리적 분포와 미소생육지의 생태)

  • Oh, Hyun-Kyung;Lee, Kyungeun;Lee, Yonghak;Choung, Yeonsook
    • Korean Journal of Ecology and Environment
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    • v.47 no.spc
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    • pp.74-82
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    • 2014
  • A perennial plant species of Ranunculaceae, Pulsatilla tongkangensis is a very rare species only found in limestone vegetation of South Korea. It is not only rare but also has great value as a horticultural resource, thus resulting in serious problems of overexploitation and habitat disturbance. For the conservation of the rare species and its development as a resource, the study was conducted with the following three aims: first, to investigate any new geographical distribution of the species; second, to identify the site condition and vegetation structure of its habitat; and third, to compare the ecology of P. tongkangensis in other microhabitats such as rock, slope and ridge area. A new distribution was found in limestone vegetation at Danyang-gun, Chungcheongbuk-do. It was, therefore, confirmed that the distribution of P. tongkangensis exactly coincides with the area of distribution of limestone, indicating a possibility that the species might be a calcicole. 87% of the microhabitats found in rocks. Compared to P. tongkangensis, at ridges or slopes, number of P. tongkangensis plants were few in rocks. It is possibly due to the lack of microhabitats that could settle in rocky areas. Once established on rocks, however, plants grew large enough to flower with higher number of leaves and flowers per plant, resulting in higher flowering rate on rocky areas. Cracks in/between rocks are likely to be safe places for the plants with favorable light conditions, abundant fine particles to root down and reduced competition for resources. Yet, further research is necessary in terms of determining whether the species is indeed a calcicole, whether other limiting factors work in its establishment stage, and genetic diversity exists in the population.

Classification of Forest Vegetation Type and Environmental Properties in Limestone Area of Korea (석회암지대 산림식생의 유형과 환경특성)

  • Yun, Chung-Weon;Moon, Hyun-Shik
    • Journal of agriculture & life science
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    • v.43 no.2
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    • pp.1-8
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    • 2009
  • The limestone area covers the narrow range of the Korean Peninsula, and it consists of a peculiar ecosystem and topography. Therefore, this study on limestone area was carried out classification of vegetation type, physicochemical properties of forest soils and correlation between environment factors and vegetation types in order to furnish fundamental data for the forest management of limestone area. Forest vegetation was classified into two community groups such as Quercus variabilis community group and Quercus mongolica community group, and it was classified into eight vegetation units. Soil texture of survey sites showed largely silt loam and soil pH indicated the value of mean 7.55 in the A layer of soil profile. Content of exchangeable cation such as calcium ion ($Ca^{2+}$) and magnesium ion ($Mg^{2+}$) showed $26.04cmol_{c}/kg$ and $2.93cmol_{c}/kg$, respectively, which was about ten times higher than average of other regions of Korea. According to corelation between environmental factors and vegetation units, Q. variabilis community group was positively correlated to soil pH, slope degree and the rate of bare rock, and content of calcium ion ($Ca^{2+}$), and then Q. mongolica community group was positively correlated to altitude, respectively.

Analysis of Instances of Characteristics Land Creep on the Mine Area in Korea (우리나라 광산지역에서의 땅밀림 사례 분석)

  • Park, Jae-Hyeon;Park, Seonggyun
    • Journal of Korean Society of Forest Science
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    • v.107 no.4
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    • pp.393-401
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    • 2018
  • The aim of this study was to analyze the characteristics of ground subsidence and land-creeping in four mining areas in Korea. Land creeping were occurred by large-scale sinkholes and tensile cracks in the mining areas. This ares showed the shape as large-scale landslides by the collapsed stone debris pushed in the direction of gravity. The rock type in the No. 4 survey area was sandstone and shale, whereas that of other three areas was limestone. The limestone was generally vulnerable to land creeping. The ground subsidence and land creeping in four mining areas were located near the ridge of the mountain. The land creeping by ground subsidence in the mining areas showed complex shapes due to the cavity of underground tunnel and the colluvial debris by gravity in the mountain area, whereas the land creeping in Korea are in the shape of landslide. The average slope of the mining area was ranged from $30.4^{\circ}$ to $33.7^{\circ}$. The values were higher ($1.5^{\circ}{\sim}4.8^{\circ}$) than the average slopes for landslide areas.