• 제목/요약/키워드: Rock-fall

검색결과 115건 처리시간 0.027초

한탄강 용암대지의 재인폭포와 개석곡의 지형 형성 (Geomorphological Processes of Jaein Waterfall and Dissection Valley in Hantangang Lava Plateau, Central Korea)

  • 이민부;이광률
    • 한국지형학회지
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    • 제24권3호
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    • pp.47-59
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    • 2017
  • This study aims to analyze geomorphologically Jaein Falls in Hantangang Lava Plateau for the landform structure, landform classification, falls dissection and recession. The height and recession length of the Falls are approximately 18m and 340m. after dissection valley arrive at area of the Jijangbong Volcanic Rock Complex of Mesozoic era, the fall will disappear. The structure of the dissection valley shows totally well vertical columnar joint near falls and plunge pool, colluvial talus deposits toward lower reach by the freezing-thawing and wet-dry activities, and alluvial cone and delta in estuary to Hantangang River. The Falls' age date and recession rate in the valley maybe relate to the age of the lava plateau. The estimated recession rate of the fall should be 8.75m/ka to 2.3m/ka, depending on the age 500ka to 40ka in lava plateau.

해양시료도서관에 입고된 심해저 망간단괴 시료 현황 (Status of Manganese Nodule Samples in the Library of Marine Samples)

  • 이현복;김원년;고영탁;오재룡;지상범
    • Ocean and Polar Research
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    • 제36권4호
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    • pp.515-524
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    • 2014
  • The Korea Institute of Ocean Science and Technology has acquired detailed biological, chemicophysical, and geological data in the northeastern Pacific through a manganese nodule program since 1983. Plenty of manganese nodules were collected to estimate the amount of resources by free-fall grab and box corer. The collected manganese nodules have been archived systematically in the rock and mineral storage section of the Library of Marine Samples (LIMS) since 2012. The LIMS provides essencial information on the stored samples including sample name, nodule type, sampling location, depth, and equipment. Although a high quality database of the information system is under construction, the samples have tagged information for manganese nodules like chemical composition, morphology, weight, size, abundance, and photograph. In this study, we attempted to provide information on the well-organized and easily accessible archived manganese nodule samples for future studies and to introduce the usefulness of the LIMS.

노천광산의 발파분진 비산영역 예측에 관한 연구 (Study on Simulation of Dust Diffusion at Open Pit Mines)

  • 김복윤;이상권;조영도;김임호
    • 터널과지하공간
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    • 제8권3호
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    • pp.194-199
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    • 1998
  • 본 연구는 석회석 노천채광장의 발파 분진이 주변을 통과하는 특고압 선로에 어느정도 비산 퇴적할 것인지, 어떤 문제를 일으킬 것인지를 평가하기 위한 연구였다. 발파 현장이 분진 발생량 및 입도분포는 그간의 연구 실적도 있고 계측도 가능하지만 얼마만큼의 분진이 어느 정도 거리까지 비산 퇴적할 것인지를 예측하기란 매우 어려운 일이다. 따라서 본 연구에서는 최근 개발한 바 있는 수치유체역학(CFD)을 이용한 3차원 유체거동 해석 프로그램(3D-Flow)을 이용하여 송전선로에 미치는 영향을 예측하는 시도를 하였다. 지형조건, 기상조건에 따른 시뮬레이션을 통하여 석회석 분진은 송전선로에 큰 영향을 미치지 않을 것으로 판단 되었다.

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석포(石浦)-덕구간(德邱間)에 분포(分布)하는 소위(所謂) 홍제사화강암(洪濟寺花崗岩)의 지질연대(地質年代)와 생성과정(生成過程)에 대(對)한 硏究(연구) (Geochronology and Petrogenetic processes of the so-called Hongjesa granite in the Seogpo-Deogku Area)

  • 김용준;이대성
    • 자원환경지질
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    • 제16권3호
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    • pp.163-221
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    • 1983
  • Main aspects of this study are to clarify geochronology and petrogenetic processes of the so-called Hongjesa granite, which is a member of various intrusive rocks exposed in the northeastern part of the Ryongnam Massif, one of the Precambrian basements of South Korea. In this study, the Hongjesa grainte is divided into four rock units based on the geologic age, mineralogical and chemical constituents, and texture: the Precambrian Hongjesa granite gneiss (Hongjesa granite Proper) and leucogranite gneiss, the Paleozoic gnessic two mica granite, and the Jurassic muscovite granite. The Hongjesa granite gneiss is identified by its grayish color, slight foliation, and porphyroblastic texture. The leucogranite gneiss is distinct by its light gray color, sand medium to coarse grained texture. The gneissic two mica granite is distinguished from others by its strong foliation, containing gray-colored feldspar phenocrysts with biotite and muscovite in varying amounts. The muscovite granite occurs as a small stock containing feldspar phenocrysts along margin of the stock. These granitic rocks vary widely in composition, reflecting the facts that they partly include highly metamorphosed xenolith and schlierens as relics of magmatic and anatectic processes. In particular, grayish porphyroblasts of microcline perthite is characteristic of the Hongjesa granite gneiss, whereas epidote and garnet occur in both the Hongjesa granite gneiss and leucogranite gneiss. These minerals are considered to be formed by potassic metasomatism and contamination of highly metamorphosed rocks deeply buried under the level of the Hongjesa granite emplacement. The individual synchronous granitic rocks plotted on Harker diagram show mostly similar trends to the Daly's values. The plots of the Hongjesa granite gneiss and gneissic two mica granite concentrate near the end part of the calc-alkalic rock series on the AMF diagrams, whereas those of the leucogranite gneiss and muscovite granite indicate the trend of the Skaergaard pluton. These granitic rocks plotted on a Q-Ab-Or diagram (petrogeny's residua system) fall well outside the trough of the system. This can be attributed to the potassic matasomatism of these rocks. On the ACF diagram, these rocks appear to be dominantly I-type prevailing over S-type. The K-Ar ages, obtained from a total of 7 samples of the leucogranite gneiss, gneissic two mica granite, muscovite granite, porphyritic alkali granite, and rhyolitic rock, in addition to the Rb/Sr ages of the Hongjesa granite gneiss by previous workers, permit the rock units to be arranged in the following chronological order: The middle Proterozoic Hongjesa granite gneiss (1714-1825 m.y.), the upper proterozoic leucogranite gneiss (875-880 m. y.), the middle Paleozoic gneissic two mica granite (384 m. y.) the upper Jurassic muscovite granite (147 m. y.), the Eocene alkali granite (52 m. y.), and the Eocene rhyolitic rock (45 m. y.). From the facts and data mentioned above, it is concluded that the so-called Hongjesa granite is not a single granitic mass but is further subdivided into the four rock units. The Hongjesa granite gneis, leucogranite gneiss, and gneissic two mica granite are postulated to be either magmatic or parautochtonous, intrusive, and the later muscovite granite is to be magmatic in origion.

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Microbial contamination including Vibrio cholerae in fishery auction markets in West Sea, South Korea

  • Choi, Yukyung;Lee, Yewon;Lee, Soomin;Kim, Sejeong;Lee, Jeeyeon;Ha, Jimyeong;Oh, Hyemin;Shin, Il-Shik;Yoon, Yohan
    • Fisheries and Aquatic Sciences
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    • 제22권11호
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    • pp.26.1-26.7
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    • 2019
  • Background: The monitoring of pathogens of fishery auction markets is important to obtain safe fishery products regarding hygiene and sanitation. In this study, aerobic, coliform, Escherichia coli, and Vibrio cholerae were monitored in the fishery products and environmental samples obtained from fishery auction markets. Methods: The fishery products (flounder, octopus, skate, rock cod, sea bass, snail, monkfish, flatfish, comb pen shell, corb shell, conger eel, hairtail, croaker, and pilchard) were placed in filter bags, and the environmental samples (samples from the water tanks at the fishery auction markets, seawater from the fishery distribution vehicles, ice from wooden or plastic boxes, and surface samples from wooden and plastic boxes used for fish storage) were collected. Aerobic bacteria, E. coli, and coliform in the samples were enumerated on aerobic count plates and E. coli/coliform count plates, respectively. For V. cholerae O1 and V. cholerae non-O1 quantification, most probable number (MPN)-PCR analysis was performed. Results: Aerobic and coliform bacteria were detected in most samples, but E. coli was not detected. Wooden boxes were contaminated with high levels of aerobic and coliform bacteria in all seasons (spring, summer, and fall). During fall, V. cholerae non-O1 were detected in snails, hairtails, croakers, flatfishes, pilchards, plastic boxes, and water samples. Conclusions: These results indicate an increased prevalence of V. cholerae contamination in fishery products in fall, including food contact samples, which can be vehicles for cross-contamination.

경주 분황사석탑의 풍화훼손도 평가와 보존과학적 진단 (Deterioration Assessment and Conservational Scientific Diagnosis of the Stone Pagoda in the Bunhwangsa temple, Gyeongju, Korea)

  • 이정은;이찬희;이명성
    • 보존과학회지
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    • 제18권
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    • pp.19-32
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    • 2006
  • 경주 분황사석탑은 암석을 벽돌 모양으로 다듬어 쌓아올린 모전석탑으로서, 모전석을 이루는 암석은 주로 안산암질암이다. 전석은 부분적으로 모서리 마모와 균열이 발생되어 있으며 다중박리와 박락, 양파껍질과 같은 분해, 구열상 균열 및 암편상 탈락이 진행 중이다. 화강암질암으로 구성된 기단부와 동서남북 방향의 감실 및 인왕상은 지의류와 이끼류에 의한 피복오염이 심하며 부분적으로 암흑색 및 황갈색 이차 수화물에 의한 무기오염물도 관찰된다. 또한 강수의 침입에 의한 상대적 수분 유지시간이 긴 감실이나 북쪽 탑신 부분은 매우 습한 상태이다. 이런 부분에서는 방해석, 석고, 점토광물 등과 같은 수화성 이차광물과 염화물의 결정화에 의해 박리와 박락이 촉진되고 있다. 삼층 옥개석의 경우 탑의 전반적인 불균형으로 인해 부재의 균열 및 이탈이 발생되어 있어 전석의 교체와 보강이 필요하다. 동남쪽 사자상과 동북쪽 사자상은 알칼리 화강암이며 . 서남쪽 및 서북쪽 사자상은 암편질 응회암이다. 이 석탑의 총표면부재수는 9,708개이며 균열된 부재는 11.0%, 암편 탈락부재는 6.7%이며 이차적 오염물질이 피복된 부재는 전체의 7.0%에 달한다. 이 석탑은 환경변화와 물리적, 화학적 및 생물학적 요인의 표면풍화에 의해 석재 자체의 기능이 저하되어 있으므로 장기적인 모니터링과 함께 종합적인 보존방안을 연구해야할 것이다.

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GIS를 이용한 야생동물의 공간적·환경적 분포특성 분석: 강원도 백두대간 보호지역을 대상으로 (The Spatial and Environmental Characteristics Analysis of Wild Animals Using GIS: a Case Study of Baekdudaegan Region, Gangwon-do)

  • 박정묵;이정수
    • Journal of Forest and Environmental Science
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    • 제29권1호
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    • pp.90-98
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    • 2013
  • The purpose of this study was to understand the geographical and environmental distribution of wild animals in Baekdudaegan region using field survey and GIS data. Crucial factors were selected and analyzed to understand the distributional characteristics of wild animals (7 species in 6 families) and rare endemic plants (14 species in 11 families). These crucial factors include stand factors (forest type, DBH class, and crown density), soil factors (bed rock, soil texture, and organic matter), geographical factors (elevation, slope, aspect) and climatic factors (temperature, rain fall, humidity). Finally, 10 factors were selected by statistical analysis and categorized for analyzing geographical and environmental features. Four families such as Muridae, Sciuridae, Suidae and Talpidea in wild animal showed the similar habitat characteristics with the 10 factors.

암반과 그라우팅 접촉면의 부착력 평가를 위한 실내 실험 (Evaluation for Bond between Rock and Grouting)

  • 김영욱;박지호;조성국;허갑수;이충렬;정경한
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2009년도 추계학술발표논문집
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    • pp.868-870
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    • 2009
  • 이 연구에서는 암반에 마이크로 파일을 그라우팅하여 시공할 경우에 암반과 그라우트 접촉면에 발생되는 부착력을 특수 제작된 부착력실험용 몰드와 만능시험기를 이용하여 측정하고 그라우팅 방법(압력식, 중력식)을 달리하여 비교 분석하였다. 실험결과 압력식의 부착력과 일축압축강도가 중력식보다 크게 나타났다.

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충전물에 의한 암반사면 붕괴사례 (Case Study on Failure of Rock Slope Caused by Filling Material)

  • 김용준;김선기;김주화
    • 한국산학기술학회:학술대회논문집
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    • 한국산학기술학회 2007년도 춘계학술발표논문집
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    • pp.87-90
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    • 2007
  • 셰일층으로 구성된 암반사변에서 층리면을 따라 대규모 평면파괴가 사연 중앙부에서 발생하였다. 현장조사시 파괴사면 주변은 지하수 누수 흔적과 점토층의 충전물이 존재하였으며, 파괴원인을 검토한 결과 층리면을 따라 형성된 점토 충전물의 낮은 전단강도와 강우시 인장균열내 형성된 수압에 의해 붕괴가 발생한 것으로 나타났다. 그리고 충전된 절리면의 전단강도 특성을 규명하기 위해서 모래, 점토의 인위적인 충전물을 이용하여 충전재 두께비에 따른 전단강도 특성을 고찰하였다.

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지하 공동에 대한 탄성파 속도 및 진폭 변화에 관한 연구 (A study of seismic velocity and amplitude variation around underground cavity)

  • 이상철;오석훈;손권익;서백수
    • 산업기술연구
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    • 제27권A호
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    • pp.9-14
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    • 2007
  • This study was designated to clarify the aspect of the wave propagation around the cavity. The change of traveltime and amplitude of the seismic wave was observed according to the various wave velocities of the cavity. The seismic wave detour or penetrate the cavity depending on the seismic velocity of the in-filled material. Generally, seismic wave detours toward high velocity zone around the cavity, and when the velocity of the cavity material reaches to 80 % of the base rock, the wave penetrates the cavity. The traveltime of the detouring seismic wave is not sensitive to the change of the cavity velocity, but as the velocity of the cavity increases, the fall of the amplitude was reduced. The penetrating wave showed the steeply increasing amplitude due to the reiteration of the detouring wave.

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