• Title/Summary/Keyword: 지질경계

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Geological Linear Feature Extraction using Space-borne Imagery : Experimental Cases in Jeongsun Area (위성영상을 이용한 지질학적 선구조의 자동 추출 : 정선지역 사례 연구)

  • 류희영;이기원;박노욱;권병두
    • Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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    • 2004.03a
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    • pp.635-640
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    • 2004
  • 절리, 단층, 습곡, 암맥, 파쇄대 및 암상의 경계에 의해 나타나는 지질학적 선구조는 지하의 물성이나 지질구조를 반영한다. 따라서 지구조 운동 분석을 위한 기초 자료로 이용가능하기 때문에 그동안 전문가의 육안 판독이외에 영상에서 선구조를 추출하기 위한 많은 연구가 이루어져왔다. 최근에 이용 가능한 위성영상자료가 증가하고 영상을 지구과학 응용분야에 적용하는 사례가 많아짐에 따라 영상으로부터 선구조를 빠르고 정확하게 추출해야 할 필요성이 높아졌다. 본 연구에서는 위성영상으로부터 선구조를 자동으로 추출하기 위해 구배 방향 프로파일 분석(Gradient Direction Profile Analysis. GDPA) 알고리즘과 Hough 변환 알고리즘을 이용한 프로그램을 개발하였고, 각 알고리즘에 필요한 모든 변수들을 사용자가 직접 입력할 수 있도록 설계하였다. 이 프로그램을 옥천 습곡대의 북동부에 위치한 강원도 정선지역의 Landsat TM 에 적용하여 가능성을 검토에 보았고, 오차 검증 방법을 이용하여 각 알고리즘을 정량적으로 평가하였다.

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Case Study on Rock Slope Failures Caused by Geologic Structures (지질구조 영향에 의한 암반비탈면 붕괴 사례 연구)

  • Park, Boo Seong;Cho, Hyun;Park, Dong In;Kim, Jun Ho;Choi, Jae Ho
    • The Journal of Engineering Geology
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    • v.27 no.4
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    • pp.417-427
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    • 2017
  • This study aims to present cases of rock slope failures caused by geological structures. Status of slope failures, results of cause analysis and stabilizing methods are introduced, focusing primarily on rock slope failures caused by specific geologic structures, such as intersection of faults infilled with clay, foliation and fault shear zone by dike intrusion and deep-seated clayey layer along lithologic boundary. Detailed geological survey, geophysical exploration and boring survey were conducted for cause analysis. Stabilizing method to prevent further slope failures and to ensure long-term stability of slopes were established, considering characteristics of geological structures, types of failure and geological conditions.

Numerical Modeling of Seawater Intrusion in Coastal Aquifer (연안 대수층에서 해수침투 축성 해석)

  • 이연규;이희석
    • Tunnel and Underground Space
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    • v.14 no.3
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    • pp.229-240
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    • 2004
  • Coastal aquifers may serve as major sources fur freshwater. In many coastal aquifers, intrusion of seawater has become one of the major constraints imposed on groundwater utilization. The management of groundwater in coastal acquifers means making decision as to the pumping rate and the spatial distribution of wells. Several numerical techniques for flow and solute transport simulation can provide the means to achieve this goal. As a basic study to predict the intrusion of seawater in coastal phreatic aquifers, the coupled flow and solute transport analysis was conducted by use of the 3-D finite element code, SWICHA. In order to understand how the location and the shape of freshwater-seawater transition zone were affected by the boundary conditions and hydrogeologic variables, parametric study was carried out.

Estimation of Site Effects at Hongsung Based on 2-Dimensional Basin Modeling within Spatial Geotechnical Information System (공간 지반 정보 시스템을 활용한 2차원 분지 모델링 기반의 홍성 지역 부지 효과 평가)

  • Sun, Chang-Guk;Choo, Yun-Sik;Chung, Choong-Ki
    • 한국방재학회:학술대회논문집
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    • 2008.02a
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    • pp.253-256
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    • 2008
  • 지하 토사 조건 및 지질 구조는 지진 시 지반 운동의 증폭에 관련된 부지 효과에 매우 큰 영향을 미친다. 본 연구에서는 국내 홍성 지역을 대상으로 시추 조사와 현장 탄성파 시험을 포함한 현장 조사 및 지표 부근지질 정보를 획득하기 위한 부지 답사를 통해 부지 효과를 확인하였다. 홍성 지역은 1978년 계기 지진이 발생한 지역으로서 기반암 상부에 최대 약 50 m 두께의 풍화대 지층이 분포한다. 연구 대상 지역의 공간 지층 구조를 효율적으로 확인하기 위하여 지리정보시스템(GIS) 기법 기반의 지반 정보 시스템(GTIS)의 구축하였으며, 홍성 지역은 분지는 얕고 넓은 형상임을 확인하였다. 홍성 지역의 부지 지진 응답을 평가하기 위하여 대표 단면에 대한 2차원 유한 요소 해석을 수행하였다. 도출된 지진 응답으로부터 지반 운동이 기반암 상부 토사층을 통해 전단파가 전파되면서 증폭되고 분지 형상에 따른 전단파의 상호 작용으로 생성된 표면파로 인해 분지 경계 부근 진동 지속 시간이 증가됨을 확인하였다. 뿐만 아니라, 분지 내의 선정된 토사 부지들에 대해서 추가적인 1차원 유한 요소 지진 응답 해석을 수행하였으며, 본 연구 대상 분지가 매우 얕고 넓음에 따라 분지 경계 부근을 제외하고는 분지 내 대부분의 위치에서 2차원 지진 응답과 유사한 결과를 보였다.

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Ground Characterization of the Cheongju Granite Area Using the Geophysical Methods (물리탐사를 이용한 청주 화강암 지역의 지반특성 파악)

  • Kim Ji-Soo;Han Soo-Hyung;Seo Yong-Seok;Lee Yong-Jae
    • The Journal of Engineering Geology
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    • v.15 no.1
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    • pp.41-55
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    • 2005
  • This research is aimed at investigating the ground characterization of the Cheongju granite area using the geophysical methods. Test site was chosen from the building site in Chungbuk University, Chongju, Chungbuk province. Furthermore, geophysical methods are employed on the outcrops in the east to map the distribution of fault and intrusion and reveal the degree of weathering. The subsurface structure mapped from seismic re-fraction survey mainly consists of two units of weathered soil and rock. Threshold of the units were determined on the basis of seismic velocity of 800 m/s, supported from the standard classification table. From the results of standard penetrating test(SPT), these units are found to show medium-high and high density, respectively. Weathering soil is subdivided in unsaturated layer and saturated layer with thresholds of seismic velocity (500 m/s) and resistivity (200 ohm-m). In particular, unsaturated layer is again classified into dry and wet portions using the GPR section. The boundary between unsaturated and saturated weathering soils corresponds to the groundwater table at depth of approximately 5~6.2 m, which is well correlated with the one from drill-core data. However, bedrock is not delineated by geophysical methods. In the GPR section, fault and intrusion observed on the outcrop are revealed not to extend to the building site. With respect to weathering degree, the outcrop characterized by low resistivity and velocity corresponds to the grade of 'completely weathered' from the geotechnical investigations.

Structural Geometry of a Regional-scale Overturned Fold in the Daecheong Island, Central-western Korean Peninsula (한반도 중서부 대청도에 발달하는 광역규모 과습곡의 구조기하학적 특징)

  • Jeong-Yeong Park;Deung-Lyong Cho;Seung Hwan Lee;Yujung Kwak;Seung-Ik Park
    • Economic and Environmental Geology
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    • v.57 no.1
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    • pp.41-50
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    • 2024
  • This study reports the structural geometry and folding mechanism of a regional-scale overturned fold in the Daecheong Island, central-western part of the Korean Peninsula. Based on low-hemisphere stereographic and down-plunge projections using data from a detailed field survey, we classify the regional-scale fold as an open overturned fold shallowly plunging toward NE. The asymmetric and symmetric parasitic folds in the limb and hinge zones indicate layer-parallel shortening prior to flexural-flow folding. Fold dating must be required to decipher the orogenic process causing the regional-scale overturned fold in the Daecheong Island.

Interpretation of High-resolution Seismic Data in the Middle Part of the Pungam Basin, Korea (풍암분지 중부지역의 고해상도 탄성파자료 해석)

  • Kim, Gi Yeong;Heo, Sik
    • Journal of the Korean Geophysical Society
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    • v.2 no.3
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    • pp.201-208
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    • 1999
  • A high-resolution seismic profile acquired across the middle part of the Pungam Basin, one of the Cretaceous sedimentary basins in Korea, has been interpreted to delineate subsurface geological structures. Boundary faults, intrusive bodies, and unconformity surfaces are identified on the seismic section. Basin fills are divided into five depositional units (Units I, II, III, IV, and V in descending order). The normal faults were formed by transtentional movement along a sinistral strike-slip fault zone. Unconsolidated sediments, a weathered layer, and sedimentary layers overly the Precambrian gneiss. The granite body intruded at the southeastern part contacts the adjacent sedimentary rocks by a near-vertical fault. Granitic intrusions caused tectonic fractures and normal faults of various sizes. An andesitic intrusive body indicates post-depositional magmatic intrusions. Continuous strike-slip movements have deformed basin-filling sediments (Units I and II).

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Stratigraphic and Structural Review of Yeoncheon Group and Iimjingang Fold Belt, and Its Edge of Distribution (연천층군과 임진강습곡대의 층서.구조적 재고 및 분포 경계)

  • Chwae, Uee-Chan;Choi, Sung-Ja
    • Economic and Environmental Geology
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    • v.42 no.6
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    • pp.627-634
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    • 2009
  • Redefining the difference among the Yamaguchi's 'so-called Yeoncheon system,' north Korean's 'Rimjin System' and Yeoncheon Group of national geological map, authors tried to avoid a possible misunderstanding of concept between Yeoncheon Group and Imjingang fold Belt. As a tool of preliminary geological mapping and or N-S reconnaissance of the whole Yeoncheon Group, an interpretation technique of satellite image from various angles has been applied to understand the geometrical attitude of strike and dip of random spot, and a further concept like as cross section.

Studies on the Food & Daily Habits and Lipid Concentrations in Serum of Adult Man (성인 남자의 식습관과 혈중지질 농도에 관한 연구)

  • 황보진향;손양아;신승렬;윤광섭;김광수
    • Food Industry And Nutrition
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    • v.7 no.2
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    • pp.45-50
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    • 2002
  • 본 연구는 성인 남자의 식생활 형태가 혈중지질 농도에 미치는 영향을 연구하기 위한 기초적인 연구로 영남의료원의 건강피검진자를 대상으로 식습관, 영양소 섭취량, 혈중지질농도를 조사하였다. 전체 조사대상자 220명중에 정상인 133명(60.5%), 경계수준군과 고콜레스테롤환자군은 각각 62명(28.2%)과 25(11.3%)를 차지하였다. 조사대상의 평균연령은 $48.4\pm9.5$세이었고, 체중은 $67.7\pm10.2kg$이었다. 평균 Broca's 지수(RBM)와 체질량지수(BMI)는 각각 $109\pm14.3$, $23.6\pm3.0$이었다. 식습관이 좋은 사람이 12명(5.4%)이고 보통인 사람이 130명(59.1%)에 해당하였으며 나쁜 사람이 78명(35.5%)으로 나타났으며, 식사형태와 식품의 배합에 대한 인식이 부족한 것으로 나타났다. 조사대상자의 혈중 중성지질의 평균농도는 약 115.8mg/dL이었고, $90\sim120mg/dL$인 사람이 대상자 220명중에 131명으로 전체의 59.9%를 차지하였다. 조사 대상자의 혈중 콜레스테롤 농도의 평균은 192.4mg/dL이었고, 혈중 콜레스테롤의 농도에 따른 대상자의 분포는 $180\sim210mg/dL$인 대상자가 73명으로 전체의 33.2%를 차지하여 가장 많았고 $150\sim210mg/dL$사이 포함되는 사람이 전체의 60.5%로 133명인 것으로 나타났다.

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Policy Suggestions for Geological and Geotechnical Information Management in Earthquake Hazard Mitigation Measures by Local Governments (지자체 지진방재 대책을 위한 지질과 지반정보관리 정책 제언)

  • Lim, Hyunjee;Song, Cheol Woo;Ha, Sangmin;Kim, Min-Cheol;Son, Moon
    • Journal of the Korean earth science society
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    • v.43 no.1
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    • pp.176-187
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    • 2022
  • Due to recent mid-scale earthquakes in the Korean Peninsula, the Korean central and local governments are preparing new measures for earthquake hazard mitigation. Geological and geotechnical information is essential for earthquake hazard assessment. Thus, related data have been collected and assimilated as DBs by various national organizations. However, several problems arise when local governments intend to use this information to establish earthquake hazard mitigation measures. In the case of the geological information, small-scale geological maps make it difficult to acquire detailed information, whereas lithofacies and faults do not often match at the boundaries of large-scale geological maps. Significant geotechnical information is lost due to lack of digitalization. Present study proposes four policy plans for geological and geological information management. First, it is necessary to link industry-academictechnology fields to use the information that has already been or to be produced more efficiently and professionally. Second, local government regulations are required to be enacted and revised to accumulate a lot of geological and geotechnical information. Third an expert system should be prepared to improve the quality of the information. Fourth, it is necessary to establish a dedicated department and expand budget support for efficient information management.