• Journal of the Korean Geographical Society
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• v.34 no.4
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• pp.355-370
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• 1999

본 연구에서는 유역 분지의 지형 조건이 상이한 영서 및 영동 하천들을 대상으로 하상 퇴적물 입경과 하도 경사의 경향성, 그리고 이들간의 상관관계를 중점적으로 조사하였다. 조사 결과, 유역 분지의 지형 조건이 다른 것과 마찬가지로, 영서 하천과 영동 하천은 퇴적물 입경 및 하도 경사의 경향성이 서로 달랐다. 영서 하천에서는 유역 면적의 증대에 따라 퇴적물 입경 및 하도 경사가 소폭으로 감소되는 경향으로 보이고 있으며, 그 경향성이 뚜렷하지 않았다. 이와는 달리, 영동 하천에서는 퇴적물 입경 및 하도 경사가 유역 면적의 증가에 따라 지수적으로 감소되었으며, 그 경향성 또한 매우 분명하였다. 한편, 영서 및 영동 하천을 모두 고려한다면, 퇴적물 입경과 하도 경사간에는 통계적으로 의미있는 상관관계가 성립되는 것으로 밝혀졌다. 그러나 이들 간의 상관관계는 영서 하천보다는 영동 하천에서 높게 나타났다. 위와 같은 사실로 미루어 볼 때, 본 연구 지역에서는 유역 분지의 지형 조건이 퇴적물 입경 및 하도 경사에 큰 영향을 미치는 것으로 나타났다.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.17 no.1
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• pp.16-24
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• 2012

To study the seasonal pattern of sediment distribution and the transport tendency in Haeundae nearshore area; i) the grain size texture of surface sediment was examined in June, October, and December of 2007, and March and June of 2008, and secondary, ii) the transport tendency was studied by using a two-dimensional sediment transport model of Gao and Collins (1992), and finally, iii) the bathymetric changes were analyzed by using the data collected in February, May, August, and December of 2007 by Haeundae District Office. Spatial distribution of sediment texture, the tendency of sediment transport as well as the bathymetric change showed significant seasonal variations. From June to December of 2007, the eastern part of the Haeundae area, off Dalmaji Hill showed the coarsening of mean grain size with a prominent transport tendency toward the Haeundae beach. On the contrary, the western part of the area, off Dongbaek Island showed a fining trend of mean grain size, and the transport tendency toward the beach was relatively weakened. From December of 2007 to June of 2008, the mean grain size of Mipo Harbor became finer, and the transport tendency toward the central beach decreased. The mean grain size of Dongbaek Island became coarser, while the tendency increased in the direction of the beach. The areas of significant net accumulation and erosion were depicted based on the bathymetric changes between observation periods. During the period of February to May of 2007, net accumulation was observed on the eastern part of the study area, in front of Mipo Harbor. Erosion was generally occurred throughout the area from May to August of 2007. From August to December of 2007, erosion and accumulation was observed off Mipo Harbor and Dongbaek Island, respectively. The change of sediment facies also suggests the accumulation on the eastern coast during the spring, erosion around the entire coast during the summer, and accumulation on the western coast during the winter. The changes in the accumulation and erosion were most apparent during the summer when several typhoons have passed by, while unnoticeable during the spring.

• Economic and Environmental Geology
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• v.37 no.2
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• pp.153-171
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• 2004

This study was carried out to define the geochemical and mineralogical relationship between stream sediments and regional geology on upstream of Hahn river area. Geochemical characteristic including for major elements, trace elements and rare earth elements of the South and North Hahn river bed sediments are similar to those of acid igneous rocks which are distributed around both Hahn river basin. The chemical variation of major elements against SiO$_2$ and trace elements contents between South and North Hahn river bed sediments doesn't show the difference. REE patterns of both area show a distinct negative Eu anomaly, but total contents of rare earth elements are higher in North Hahn river sediments than South Hahn river sediments. The heavy minerals in the river bed sediments in this study area are identified as tremolite-actinolite, hematiteㆍmagnetite, common hornblende, ilmenite, garnet, epidote, rutile and sphene. In conclusion, it is elucidated that South and North Hahn river bed sediments are being originated from igneous rocks or metamorphic rocks which contains medium-high grade metamorphic minerals and components of originated from sedimentary rocks those of politic or calcareous rocks are eroded away as solution or suspended load.

• Journal of the Korean association of regional geographers
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• v.13 no.2
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• pp.119-128
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• 2007

Grain-size trend analysis is the methodology to obtain the net sediment transport pattern from the spatial trends of grain size parameters. It has the potentials to be an effective tool to address the morphological changes of the deltaic barrier islands in the Nakdoog River once we make sure net transport patterns inferred from grain size trend analysis represent the morphological evolution patterns. This research aims to investigate the applicability of the net transport patterns obtained by 'transport vector', proposed by Gao and Collins(1992), to understanding the morphological changes of the Nakdong River deltaic barrier islands. The results indicate that the net transport directions are overall in concordance with the morphological evolution patterns; however, the level of concordance is low in the island with fast growing rate. The reasons may be match or mismatch of temporal scales involved between processes represented by net transport patterns and morphological change analyzed or the rate of morphological change. Consequently, the application of grain size trend analysis in analyzing the morphological changes of deltaic barrier islands requires the careful consideration of temporal scales involved.

• Proceedings of the Korean Association of Geographic Inforamtion Studies Conference
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• 2008.10a
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• pp.303-304
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• 2008

1970년부터 해운대 신시가지 조성 및 춘천의 복개공사, 해안 주변의 매립, 도로건설 등의 연안 관련 사업이 환경에 미치는 종합적인 영향에 대한 검토도 없이 시행되어, 해운대 백사장으로 유입되어야 할 토사가 주공급원인 육지로부터 잠정적으로 차단되었다. 해운대 해수욕장의 해빈이 갈수록 감소되고 있는 가운데, 유실된 토사가 퇴적되는 연안의 해저지형에 대한 조사를 통해 정량적인 분석과 기간별 침퇴적 경향을 알아보는 연구가 필요하다. 따라서 본 연구에서는 수심 측량 자료를 이용하여 GIS기법으로 해저지형도를 제작하였고, 해저지형을 등간격으로 나누어 각 구간별 침퇴적 경향을 분석해 보았다. 그 결과 계절별로 침퇴적을 반복하고 있었고, 여름에는 침식, 겨울은 퇴적되는 경향을 보였다.

• Journal of the Geological Society of Korea
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• v.54 no.6
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• pp.631-640
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• 2018

To understand the formation and evolution of a sedimentary basin in basin analysis and modelling studies, it is important to analyze the thickness and age range of sedimentary layers infilling a basin. Because the compaction effect reduces the thickness of sedimentary layers during burial, basin modelling studies typically restore the reduced thickness using the relation of porosity and depth (compaction trend). Based on the compilation plots of published compaction trends of representative sedimentary rocks (sandstone, shale and carbonate), this study estimates the compaction trend ranges with exponential curves and equations. Numerical analysis of sedimentary compaction is performed to evaluate the variation of porosity and layer thickness with depth at key curves within the compaction trend ranges. In sandstone, initial porosity lies in a narrow range and decreases steadily with increasing depth, which results in relatively constant thickness variations. For shale, the porosity variation shows two phases which are fast reduction until ~2,000 m in depth and slow reduction at deeper burial, which corresponds to the thickness variation pattern of shale layers. Carbonate compaction is characterized by widely distributed porosity values, which results in highly varying layer thickness with depth. This numerical compaction analysis presents quantitatively the characteristics of porosity and layer thickness variation of each lithology, which influence on layer thickness reconstruction, subsidence and thermal effect analyses to understand the basin formation and evolution. This work demonstrates that the compaction trend is an important factor in basin modelling and underlines the need for appropriate application of porosity data to produce accurate analysis outcomes.

• Proceedings of the Korea Water Resources Association Conference
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• 2005.05b
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• pp.399-403
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• 2005

이동상 하도에서 하천정비 및 안정하도 유지를 위해서는 하상변동 특성을 면밀히 파악하는 것이 중요하다. 본 연구에서 임진강을 대상으로 퇴적경향이 있는 하류구간에서의 하상층구조 조사를 포함하여 남한지역 전 구간에 걸쳐 하상재료를 직접 채취하여 입도분포를 조사하였다. 이를 토대로 하도형성을 지배하는 하도특성량 분석과 HEC-6에 의한 하상변동 예측을 통해 임진강 하강변동 특성을 파악하였다. 연구결과, 이동상 하도인 임진강에서 하상재료의 입도분포 및 하상 층구조 조사를 통하여 하상변동 특성을 파악할 수 있음을 확인하였다. 초평도를 경계로 상류(자갈하천)와 하류(모래/실트)간에 하도특성이 급변하는 경향을 확인하였다. 하도특성으로는 초평도 상류구간에서는 별다른 하상변동이 없는 반면, 감조하천구간인 장단반도 지구에서 실트/모래로 구성된 하상재료로 퇴적경향이 지속하고 있다는 사실을 확인할 수 있었다. 초평도를 전후로 하여 조석작용과 함께 지형/지질여건이 급변하는 특이성이 임진강의 하상변동에 결정적인 요소가 되고 있음을 확인하였다.

• Journal of Korean Society of Coastal and Ocean Engineers
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• v.21 no.6
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• pp.462-469
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• 2009

This study suggests a general formula of non-cohesive sediment transport rates for waves and currents which is also valid for wave only or current only condition. On-offshore sediment transport rates with the second order Stokes wave in the shallow water are calculated as the pickup rate times the distance. The formula depicts reasonably that high waves move material offshore, and low waves move material onshore. Also the formula, as is the case the waves with long period tend to move material onshore, shows good results.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.4 no.4
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• pp.338-348
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• 1999

Physical properties of mudbelt sediments in the southeastern inner shelf of Korea are studied from 14 cores. Physical properties, compressional wave velocity, and sediment texture for core sediments are analyzed. The major source of sediment in the study area is the Nakdong River. Fine-grained sediments from the river are transported northeastward by coastal circulation and the Tsushima Current, resulting in a gradual northeastward increase in porosity and a decrease in wet bulk density and velocity. The trend matches well with the bathymetry. The mean grain size appears to be the most important variable to determine the physical properties and velocity. The variations of physical properties with burial depth are dependent more strongly on sediment texture than compaction and/or consolidation. Correlations between the physical properties and the sediment texture show slight deviations from those of the continental terrace sediment in the North Pacific and inner shelf sediment in the South Sea of Korea. The velocity is higher than that of the North Pacific and the South Sea sediments between these areas. This is probably due to differences in sedimentary, environment and mineral compositions. The higher sediment velocity in the study area may also be attributed to the escape of gas from pore space which decreases void ratio.

• Journal of the Korean earth science society
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• v.26 no.3
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• pp.253-267
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• 2005

Seasonal and spatial variations of tidal flat sediments were studied in Yeoja Bay. Results of the yearly observation of tidal flat transect lines indicated that the monthly change of grain size composition was not distinct from each tidal flat transect line, but it was quite clear that clay covered $40\~70\%$ of the sediment composition. Clay composed most highest in the northern part of the bay, and lowest in the western. As clay content increased, water and organic matter showed a tendency of increase, while the mean grain size was fixed per clay amount. Shear strength came out as 0 kPa as a whole. Seasonal variations of clay contents in each tidal flat were higher in winter and spring, but lower in summer and autumn. Thefine sediments were likely to be accumulated in the winter and spring. The average accumulation rate of each tidal flat was $-14.62\~38.57mm{\cdot}yr^{-1}$. The numbers showed $32.13mm{\cdot}yr^{-1}$ in the northern, $-14.62mm{\cdot}yr^{-1}$in the western, and $6.46mm{\cdot}yr^{-1}$ in the eastern part. During the coarse of this study sediment accumulation rates indicated that the sediments deposited continuously in the northern part of tidal flat, whereas erosion occurred in the western part. However, there was no distinct change in the eastern part. It was due to the clockwise lateral circulation in Yeoja Bay. Seasonally, sedimentation happened during the dry season (winter and spring) and erosion during the wet season (summer and autumn).