• The Journal of the Petrological Society of Korea
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• v.10 no.2
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• pp.82-94
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• 2001

The main geological structure of the Ogcheon belt in the Buunnyeong area, Mungyeong, which consists of three stratigraphic sequences, Joseon and Pyeongan Supergroups and Daedong Group, is characterized by the development of ESE-vergence structural unit (Dangok unit) and WNW-vergence structural units (Samsil and Bugongni units) onto an autochthonous unit (Buunnyeong unit). Three phases of deformation are recognized in this area. The lent phase of deformation coourred under the WNW-ESE compression, forming an upright-open fold (Buunnyeong-I fold) with NNE axial trend in the Buunnyeong unit. The second phase of deformation also under the WNW-ESE compression formed the Dangok, Samsil and Bugongni units, resulting in the further closing of the Buunnyeong-I open fold, the elongation of pebbles in the conglomerate rocks of a basal sequence of the Daedong Group, recumbent folds (Buunnyeong-II fold) and drag folds (Dangok fold) with NNE axial trend in the Buunnyeong and Dangok units, respectively. The third phase of deformation formed kink folds with its axis p1unging subvertically. The first and second phases of deformation took place before and after the deposition of the Daedong Group of the Upper Triassic -Lower Jurassic, respectively. These first two deformation events, which occurred under the same WNW-ESE compressional field, produced the regional NNE trend of geological structure in the Joseon and Pyeongan Supergroups of this area.

• Disaster Prevention Review
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• v.18 no.4
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• pp.78-151
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• 2016

지난 7월 18일 "자연재해위험개선지구 관리지침(고시)" 일부를 개정(국민안전처 고시 제2016-117호)하여 복합 유형에 대한 지구지정으로 종합적인 정비근거를 마련하였다. 또한, "자연재해대책법" 제13조 및 제14조에 따라 자연재해위험개선지구 정비 사업계획 수립과 실시설계 수립을 같은 법 제38조 제2항에 따라 방재관리대책대행자로 하여금 대행하도록 개정('16.1.27)되었음을 알려 드리며, 앞으로 지방자치단체에서는 자연재해위험개선지구 정비사업 실시설계 추진 시 방재관리대책대행자로 등록되지 않은 엔지니어링사업자에게 대행하는 사례가 없도록 철저히 관리하여 주시기 바란다.

• Economic and Environmental Geology
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• v.55 no.5
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• pp.541-550
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• 2022

A pre-existing landform is created by weathering and erosion along the bedrock fault and the weak zone. A neotectonic landform is formed by neotectonic movements such as earthquakes, volcanoes, and Quaternary faults. It is difficult to clearly distinguish the landform in the actual field because the influence of the tectonic activity in the Korean Peninsula is relatively small, and the magnitude of surface processes (e.g., erosion and weathering) is intense. Thus, to better understand the impact of tectonic activity and distinguish between pre-existing landforms and neotectonic landforms, it is necessary to understand the development process of pre-existing landforms depending on the bedrock characteristics. This study used a two-dimensional numerical landscape evolution model (LEM) to study the spatio-temporal development of landscape according to the different erodibility under the same factors of climate and the uplift rate. We used hill-slope indices (i.e., relief, mean elevation, and slope) and channels (i.e., longitudinal profile, normalized channel steepness index, and stream order) to distinguish the difference according to different bedrocks. As a result of the analysis, the terrain with high erosion potential shows low mean elevation, gentle slope, low stream order, and channel steepness index. However, the value of the landscape with low erosion potential differs from that with high erodibility. In addition, a knickpoint came out at the boundary of the bedrock. When researching the actual topography, the location around the border of difference in bedrock has only been considered a pre-existing factor. This study suggested that differences in bedrock and various topographic indices should be comprehensively considered to classify pre-existing and active tectonic topography.

• Proceedings of the KSEEG Conference
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• 2005.04a
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• pp.320-323
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• 2005

• The Science & Technology
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• v.35 no.8 s.399
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• pp.40-42
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• 2002

조선조에 지구설을 옹호하다 26세로 요절한 청년 과학자 남극관은 '동창이 밝았느냐...'라는 유명한 시조를 남긴 남구만의 손자이다. 그는 자신이 쓴 글모임 "몽예집"에서 지구를 공중에 매단 달걀에 비유하면서 당시 지구설을 반대하던 많은 학자들을 비판한 청년과학자였다.

• 한국지구과학회:학술대회논문집
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• 2006.02a
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• pp.229-229
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• 2006

• The Journal of the Petrological Society of Korea
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• v.21 no.2
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• pp.129-150
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• 2012

The tectonic evolution of the Central Ogcheon Belt has been newly analyzed in this paper from the detailed geological maps by lithofacies classification, the development processes of geological structures, microstructures, and the time-relationship between deformation and metamorphism in the Ogcheon, Cheongsan, Mungyeong Buunnyeong, Busan areas, Korea and the fossil and radiometric age data of the Ogcheon Supergroup(OSG). The 1st tectonic phase($D^*$) is marked by the rifting of the original Gyeonggi Massif into North Gyeonggi Massif(present Gyeonggi Massif) and South Gyeonggi Massif (Bakdallyeong and Busan gneiss complexes). The Joseon Supergroup(JSG) and the lower unit(quartzose psammitic, pelitic, calcareous and basic rocks) of OSG were deposited in the Ogcheon rift basin during Early Paleozoic time, and the Pyeongan Supergroup(PSG) and its upper unit(conglomerate and pelitic rocks and acidic rocks) appeared in Late Paleozoic time. The 2nd tectonic phase(Ogcheon-Cheongsan phase/Songnim orogeny: D1), which occurred during Late Permian-Middle Triassic age, is characterized by the closing of Ogcheon rift basin(= the coupling of the North and South Gyeonggi Massifs) in the earlier phase(Ogcheon subphase: D1a), and by the coupling of South China block(Gyeonggi Massif and Ogcheon Zone) and North China block(Yeongnam Massif and Taebaksan Zone) in the later phase(Cheongsan subphase: D1b). At the earlier stage of D1a occurred the M1 medium-pressure type metamorphism of OSG related to the growth of coarse biotites, garnets, staurolites. At its later stage, the medium-pressure type metamorphic rocks were exhumed as some nappes with SE-vergence, and the giant-scale sheath fold, regional foliation, stretching lineation were formed in the OSG. At the D1b subphase which occurs under (N)NE-(S)SW compression, the thrusts with NNE- or/and SSW-vergence were formed in the front and rear parts of couple, and the NNE-trending Cheongsan shear zone of dextral strike-slip and the NNE-trending upright folds of the JSG and PSG were also formed in its flank part, and Daedong basin was built in Korean Peninsula. After that, Daedong Group(DG) of the Late Triassic-Early Jurassic was deposited. The 3rd tectonic phase(Honam phase/Daebo orogeny: D2) occurred by the transpression tectonics of NNE-trending Honam dextral strike-slip shearing in Early~Late Jurassic time, and formed the asymmetric crenulated fold in the OSG and the NNE-trending recumbent folds in the JSG and PSG and the thrust faults with ESE-vergence in which pre-Late Triassic Supergroups override DG. The M2 contact metamorphism of andalusite-sillimanite type by the intrusion of Daebo granitoids occurred at the D2 intertectonic phase of Middle Jurassic age. The 4th tectonic phase(Cheongmari phase: D3) occurred under the N-S compression at Early Cretaceous time, and formed the pull-apart Cretaceous sedimentary basins accompanying the NNE-trending sinistral strike-slip shearing. The M3 retrograde metamorphism of OSG associated with the crystallization of chlorite porphyroblasts mainly occurred after the D2. After the D3, the sinistral displacement(Geumgang phase: D4) occurred along the Geumgang fault accompanied with the giant-scale Geumgang drag fold with its parasitic kink folds in the Ogcheon area. These folds are intruded by acidic dykes of Late Cretaceous age.

• 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.

• The Journal of Engineering Geology
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• v.8 no.1
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• pp.35-49
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• 1998

To interpret the movement historv of the Yangsan fault, the paleostresses were analyzed from about 1,000 striated small faults and 330 extension joints which were measured from 37 sites near and along the strike of the Yangsan fault from Yangsan-si, Kyeongsangnam-do to the Shinkwang-myeon, Kyeongsangbuk-do. Six sequential tectonic events have boen established as followings: (I) NW-SE extension, (Il) ENE-WSW compression and NNW-SSE extension, (III) NW-SE compression, (W) ENE-WSW extension, (V) E-W comoression and N-S extension, and (VI) NNE-SSW compression and(VI) NNE-SSWextension. The movement history of the Yangsan fault rnrning in NNE direction were inteepreted based on these six sequential stress fields. The initial feature of the Yangsan fault was formed at the first stage with the development of extension fractures by tectonic event (I) of NW-SE extension. The fault was acted continuously with a right-1ateral strike-slip movement by tectonic event( II) closely related to event( I). The movements had been continued until the Late Miocene. This age was the most active period in faulting. The left-lateral strike-slip movement was followed by subsequent tectonic events (ffi) and (IV). The activity of the Yangsan fault was suspended temporarily by compression of tectonic event (V) which was perpendicular to the strike of the fault. This period might be very short and the magnitude of the tectonic was also small. In the last stage, the fault acted with slight extension or right-lateral moveenent by tectonic event (VI).

• 한국지구물리탐사학회:학술대회논문집
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• 2004.06a
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• pp.123-127
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• 2004