• Title/Summary/Keyword: 임진강대

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Study of Riverline Change around Sannam Wetland in the Hangang River Estuaty using LANDSAT Image Processing (LANDSAT 위성사진을 활용한 한강하구 산남습지 인근 하안선 변화 연구)

  • Youn, Sukzun;Lee, Samhee;Jang, Changhwan
    • Journal of Wetlands Research
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    • v.23 no.2
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    • pp.154-162
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    • 2021
  • The naturally opened Han river estuary is a place where the flows of the Han river, Imjin river, Yaesung river meet with West Sea of Korea, so the hydrodynamic mechanism(Impact-Response) structure of Han river estuary is complex. Continuous observation and measurement due to the morphological characteristics at the estuary are required to maintain the estuary environment and river management facilities. However, the Sannam wetland(the study area) is in the military operation area. Therefore, Sannam wetland has the limited access under the control from military office. In 2020, there had a natural disaster due to flooding in August and COVID-19, and it made a survey hard. The noncontact survey technique, the analysis of LANDSAT images at Sannam wetland, was applied to analyze riverbed fluctuation and morphological transformation around Sannam wetland. LANDSAT images obtained from EarthExplorer, USGS and analyzed by QGIS. The analysis was performed based on the area and the distance near Sannam wetland. As a result, an erosion was happened on the downstream of the study area, and the upstream of the study area did not have any serious sediment transport. Considering the resolution of LANDSAT images, this noncontect survey technique is applicable to manage the study area. From the analysis of LANDSAT images, it is assumed that the tidal effect is greater than the inflow from the upstream. The pattern change of tidal response causes the damage of the river facilities near the Hangang river estuary.

Stratigraphic response to tectonic evolution of sedimentary basins in the Yellow Sea and adjacent areas (황해 및 인접 지역 퇴적분지들의 구조적 진화에 따른 층서)

  • Ryo In Chang;Kim Boo Yang;Kwak won Jun;Kim Gi Hyoun;Park Se Jin
    • The Korean Journal of Petroleum Geology
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    • v.8 no.1_2 s.9
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    • pp.1-43
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    • 2000
  • A comparison study for understanding a stratigraphic response to tectonic evolution of sedimentary basins in the Yellow Sea and adjacent areas was carried out by using an integrated stratigraphic technology. As an interim result, we propose a stratigraphic framework that allows temporal and spatial correlation of the sedimentary successions in the basins. This stratigraphic framework will use as a new stratigraphic paradigm for hydrocarbon exploration in the Yellow Sea and adjacent areas. Integrated stratigraphic analysis in conjunction with sequence-keyed biostratigraphy allows us to define nine stratigraphic units in the basins: Cambro-Ordovician, Carboniferous-Triassic, early to middle Jurassic, late Jurassic-early Cretaceous, late Cretaceous, Paleocene-Eocene, Oligocene, early Miocene, and middle Miocene-Pliocene. They are tectono-stratigraphic units that provide time-sliced information on basin-forming tectonics, sedimentation, and basin-modifying tectonics of sedimentary basins in the Yellow Sea and adjacent area. In the Paleozoic, the South Yellow Sea basin was initiated as a marginal sag basin in the northern margin of the South China Block. Siliciclastic and carbonate sediments were deposited in the basin, showing cyclic fashions due to relative sea-level fluctuations. During the Devonian, however, the basin was once uplifted and deformed due to the Caledonian Orogeny, which resulted in an unconformity between the Cambro-Ordovician and the Carboniferous-Triassic units. The second orogenic event, Indosinian Orogeny, occurred in the late Permian-late Triassic, when the North China block began to collide with the South China block. Collision of the North and South China blocks produced the Qinling-Dabie-Sulu-Imjin foldbelts and led to the uplift and deformation of the Paleozoic strata. Subsequent rapid subsidence of the foreland parallel to the foldbelts formed the Bohai and the West Korean Bay basins where infilled with the early to middle Jurassic molasse sediments. Also Piggyback basins locally developed along the thrust. The later intensive Yanshanian (first) Orogeny modified these foreland and Piggyback basins in the late Jurassic. The South Yellow Sea basin, however, was likely to be a continental interior sag basin during the early to middle Jurassic. The early to middle Jurassic unit in the South Yellow Sea basin is characterized by fluvial to lacustrine sandstone and shale with a thick basal quartz conglomerate that contains well-sorted and well-rounded gravels. Meanwhile, the Tan-Lu fault system underwent a sinistrai strike-slip wrench movement in the late Triassic and continued into the Jurassic and Cretaceous until the early Tertiary. In the late Jurassic, development of second- or third-order wrench faults along the Tan-Lu fault system probably initiated a series of small-scale strike-slip extensional basins. Continued sinistral movement of the Tan-Lu fault until the late Eocene caused a megashear in the South Yellow Sea basin, forming a large-scale pull-apart basin. However, the Bohai basin was uplifted and severely modified during this period. h pronounced Yanshanian Orogeny (second and third) was marked by the unconformity between the early Cretaceous and late Eocene in the Bohai basin. In the late Eocene, the Indian Plate began to collide with the Eurasian Plate, forming a megasuture zone. This orogenic event, namely the Himalayan Orogeny, was probably responsible for the change of motion of the Tan-Lu fault system from left-lateral to right-lateral. The right-lateral strike-slip movement of the Tan-Lu fault caused the tectonic inversion of the South Yellow Sea basin and the pull-apart opening of the Bohai basin. Thus, the Oligocene was the main period of sedimentation in the Bohai basin as well as severe tectonic modification of the South Yellow Sea basin. After the Oligocene, the Yellow Sea and Bohai basins have maintained thermal subsidence up to the present with short periods of marine transgressions extending into the land part of the present basins.

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The Cross-sectional Mass Flux Observation at Yeomha Channel, Gyeonggi Bay at Spring Tide During Dry and Flood Season (단면 관측을 통한 경기만 염하수로의 대조기 평수시와 홍수시 유출입량 변화특성 조사)

  • Lee, Dong-Hwan;Yoon, Byung-Il;Kim, Jong-Wook;Gu, Bon-Ho;Woo, Seung-Buhm
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.24 no.1
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    • pp.16-25
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    • 2012
  • To calculate the total mass flux that change in dry and flood season in the Yeomha Channel of Gyeonggi Bay, the 13 hour bottom tracking observation was performed from the southern extremity. The value of the total mass flux(Lagrange flux) was calculated as the sum of the Eulerian flux value and stroke drift value and the tidal residual flow was harmonically analyzed through the least-squares method. Moreover, the average during the tidal cycle is essential to calculate the mass flux and the tidal residual flow and there is the need to equate the grid of repeatedly observed data. Nevertheless, due to the great differences in the studied region, the number of vertical grid tends to change according to time and since the horizontal grid differs according to the transport speed of the ship as a characteristic of the bottom tracking observation, differences occur in the horizontal and vertical grid for each hour. Hence, the present study has vertically and horizontally normalized(sigma coordinate) to equate the grid per each hour. When compared to the z-level coordinate system, the Sigma coordinate system was evaluated to have no irrationalities in data analysis with 5% of error. As a result of the analysis, the tidal residual flow displayed the flow pattern of sagging in the both ends in the main waterway direction of dry season. During flood season, it was confirmed that the tidal residual flow was vertical 2-layer flow. As a result of the total mass flux, the ebb properties of 359 cm/s and 261 cm/s were observed during dry and flood season, respectively. The total mass flux was moving the intertidal region between Youngjong-do and Ganghwa-do.

An Analysis Study of Deliberation Results to Change the Present Condition around Gyeonggi-do Designated Cultural Properties - Focusing on the Proposed Legislation 3 or More Times a Deliberations of the Cultural Properties Committee - (경기도지정문화재 주변 현상변경허가 신청안 심의결과에 관한 분석 연구 - 문화재위원회심의 3회 이상 상정안을 중심으로 -)

  • Lim, Jin-Kang;Kim, Dong-Chan
    • Journal of the Korean Institute of Traditional Landscape Architecture
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    • v.29 no.3
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    • pp.85-96
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    • 2011
  • The purpose of this study, Around Gyeonggi-do cultural propertie Change the Present Condition not apply to analyze the results of processing Change the Present Condition of the trends and issues, and characteristics are derived and In determining the basic data processing of the Change the Present Condition presented are intended to be. 248 of 2009 regulated by Gyeonggi-do Cultural Assets committee agenda for consideration of the more than three times a copy of 15 were enrolled in the study. Review the results of the Change the Present Condition permit, permit held, to review classified information and analyzes the results of processing and complementary. Application for change processing standards and their comparison with the Change the Present Condition of cultural property through the deliberations and conclusions should analyze the results. As a result of research first, decision to allow processing of the application is characterized by a variety of facilities and the lower floors many times the result of the approval, the construction of cultural property conditioned space after the application complements the exterior of the building permit has been determined, applied to the current building near where the decision to allow the existence of is the main reason Second, decisions permit held, if requested neighborhood facilities lots of facilities and construction of large-scale is the most. Results from the first hearing until a final decision is not much change in results and cultural property surroundings due to the building of the reason for rejection was the most inhibited. Third, reconsideration of the decision if the city's development projects and other large development projects, and floors of the building height did not significantly affect the change. Above all, Decisions based on the results of the presence or absence was a big acts and the reason for reconsideration, and on-site investigation is the most. Fourth, It is based on the processing of Change the Present Condition that has been passed or rejected treatment and standards of treatment in two areas where the two sections across any side of the strict criteria were applied. Cultural Properties and applications with the distance increases, the rejection and the reconsideration decision is limited Such distance did not affect the decision to allow.