• Proceedings of the Speleological Society Conference
• /
• 2002.11a
• /
• pp.19-30
• /
• 2002

카르스트 지형과 관련된 동굴생성물(Speleothems)의 발달과정은 ［그림 1］에서 요약되어 있듯이 일정한 규칙의 발달과정을 거치면서 형성되는 동굴수문학적 (Speleo-hydology)인 속성을 가지고 있다(Ford, 1989). 동굴생성물은 주로 기반암으로부터 침식되는 용해물질에 의하여 다양한 생성물을 제공하거나 외부 하천의 유입에 따른 외래산 퇴적물질 등이 상호 교차되어 집적되어있다. (중략)

• Journal of the Korean Society for Marine Environment & Energy
• /
• v.1 no.1
• /
• pp.39-46
• /
• 1998

This study presents a numerical model that can simulate changes of particle size distribution (PSD) of PCB-contaminated coastal sediments. The developed model has one spatial dimension including sedimentation and vortical dispersion as well as coagulation. The reason for considering the vortical transport mechanisms is to calculate residence time of the particles. Using the model and Initial PSD data based on actual coastal sediments contaminated with PCBs, this study shows results of model simulations. Within 48 hours of the simulation time, the PSD changed significantly and the particles were removed from water in different rates between different particle sizes. It also shows that coagulation can act an important role in this process. The model may be useful in assessing the range of resuspended sediments that can pollute neighboring areas during environmental remediation projects such as dredging.

• 한국지구물리탐사학회:학술대회논문집
• /
• 2006.06a
• /
• pp.285-290
• /
• 2006

To access the volume of sediments deposited after construction of the Soyang Dan and to understand their distribution in the Soyang lake, acoustic profiling using a 10-20 kHz system was conducted along profiles of 227 km length. Profile intervals are approximately 50 and 500 m for longitudinal and cross lines, respectively. The data were gain-controlled and then migrated using the f-k algorithm. After digitization of boundaries of the sediments, the acoustic interpretation was verified through correlating with 38 core samples. Thickness of the sediments averages 0.25 m and reaches to 8.25 m at maximum. Estimated total volume of the sediments based on anisotropic models in geostatistical methods is approximately $5.9{\times}10^6\;m^3$, which is more than twice greater than the earlier estimation based on an isotropic model.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
• /
• v.3 no.3
• /
• pp.149-157
• /
• 1998

Seasonal changes of topography, sediment grain size and accumulation rate in the Gomso-Bay tidal flat, west coast of Korea, have been studied in order to understand the seasonal accumulation pattern and preservation potential of the tidal-flat sediments. Seasonal levelings across the tidal flat show that the landward movement of both intertidal sand shoals and cheniers accelerates during the winter and typhoon periods, but it almost stops in summer when mud deposition is instead predominant at the middle and upper tidal flats. Seasonal variations of mean grain size were largest on the upper part of middle tidal flat where summer mud layers were eroded during the winter and typhoon periods. Measurements of accumulation depths from sea floor to basal plate reveal that accumulation rates were seasonally controlled according to the elevation of tidal-flat surface. The upper tidal flat where the accumulation rate of summer was generally higher than that of winter was characterized by a continuous deposition throughout the entire year, whereas in the middle tidal flat, sediment accumulations were concentrated in winter relative to summer and were intermittently eroded by typhoons. The lower tidal flat were deposited mostly in winter and eroded during summer typhoons. Can cores taken across the tidal flat reveal that sand-mud interlayers resulting from such seasonal changes of energy regime are preserved only in the upper part of the deposits and generally replaced by storm layers downcore. Based on above results, it is suggested that the storm deposits by winter storms and typhoons would consist of the major part of the Gomso-Bay sediments.

• Journal of the Speleological Society of Korea
• /
• no.89
• /
• pp.46-58
• /
• 2008

동굴 퇴적물의 형성과정은 1단계 기권 (Atmosphere): 빗방울 (H2O) 이 대기중에서 CO2의 혼합으로 산성비 (H2CO2)가 되어 석회암 (CaCO3)에 떨어져서 최초의 용식작용이 시작된다. 2단계 토양권 (Pedosphere): 산성비와 석회암성분이 합쳐 형성된 가용성 화합물 (Ca(HCO3)2)은 식생부식(植生腐植)에 의한 토양 (Humic acidic soils) 에 의해 기반암의 용식이 촉진 되어 지표에는 Karren과 석문 (석문(石門) Natural Bridge), 와지 (Dolines, Sinkholes) 지형을 형성시키고, 암석의 분순물은 지표에 남겨져서 결국 적색풍화토 (Residuum, Risidual Redish Soils) 를 만든다. 3단계 암권 (Lithosphere): 용식작용에 의해 지상에서 지하 로 확대되어진 모암의 균열을 타고, 지하의 공간이 지하수의 유입과 유출에 의해 점차 확대되어 동공형의 Conduites; Voids; Shaft 이라는 특수지형을 형성시키고,동굴의 천정으로부터 나온 Ca(HCO3)2 는 탄산염의 지속적인 분해 공급에 의해 동굴내에는 종류석, 석순, 유착석 (Speleothem)등의 새로운 동굴지형 (Speleoscape)을 조성하게 된다. 4단계 수권 (Hydrosphere): 동굴의 형성작용을 거친 물은 동굴지하수로 잔여 Calcite를 함유한 채로 유출 (Spring) 된다. 동굴을 떠난 잔여 Calcite는 또다시 하천유역에 침전시켜서 석회화 단구형의 집적지형 (Tufa Formation: Tufa Dam, Tufa Flowstone)을 최종적으로 동굴을 나와 외벽 이나 하천의 바닦에 형성하는 과정을 거치면서 카르스트 지형의 발달과정이 1차적인 순환을 마치게 된다.

• Journal of the Korean association of regional geographers
• /
• v.13 no.1
• /
• pp.43-53
• /
• 2007

Rapid geomorphic changes occur in Nakdong River deltaic coast which is composed of deltaic barrier islands and tidal flats. We investigate the pattern of these rapid geomorphic changes by analyzing the distributions of sediment grain size characteristics. The distributions of sediment grain size characteristics analysis is a very efficient method to explain geomorphic changes of deltaic barrier islands. In sediments from Jinwoo Island, Sinja Island, and Doyo Island which are composed of Nakdong River deltaic coast, mean particle size increases to onshore direction and become coarser in tidal inlets. All sediments are very well sorted. Though almost sediments show little negative skewness, several sediments from tidal inlets show negative skewness. These results provide that the stronger and more regular energies affect Nakdong River deltaic coast and make fine sediments selectively move toward tidal inlets. Because of this mechanism, the recurved spits of deltaic barrier islands enlarge.

• Journal of the Korean Geographical Society
• /
• v.41 no.4 s.115
• /
• pp.391-403
• /
• 2006

The Hanon volcano located in the southern pan of Cheju Island, Korea has a wetland in its crater being used as a farmland. Previous researchers presumed this wetland was a maar lake in the past. Based on the seismic refraction method, the wetland sediment layer was estimated between 5 to 14 m deep, which is mostly in accordance with previous researches. However, this shows only the depths at some sites, not representing the whole spatial distribution. This study is an attempt to reconstruct the volcanic lake in Hanon crater by applying the spatial statistical techniques based on the depth information from the seismic survey and known data. The procedure of reconstruction is as follows: First, the depth information from the seismic survey and known data were collected and it was interpolated by IDW and Ordinary Kriging method. Next, with the interpolation map and the present DEM the paleo DEM was constructed. Finally, using the paleo lake level on core data, the boundary of volcanic lake was extracted from the paleo DEM. The reconstructed lake resembles a half-moon in the north of the central scoria cone. It is estimated that the lake was 5 m deep on average and 13 m deep at the deepest point. Although there are slight differences according to the interpolation techniques, it is calculated that the area of the lake was between 184,000 and $190000m^2,$ and its volume approximately $869,760m^3$. Because of the continuous deposition processes after the crater formation, the reconstructed volcanic lake would not indicate an actual lake at a specific time. Nevertheless, it offers a significant clue regarding the inner morphology and evolution of the crater.

• Journal of the Mineralogical Society of Korea
• /
• v.32 no.4
• /
• pp.235-247
• /
• 2019

The Central South Sea Mud (CSSM), developed in the Seomjin River estuary, is known to be supplied with sediments from Heuksan Mud Belt (HMB) and Seomjin River. However, in order to form a mud belt, more sediments must be supplied than supplied in the above areas. Therefore, research on additional sources should be conducted. In this study, clay minerals, major elements analyzes were performed on cores 16PCT-GC01 and 16PCT-GC03 in order to investigate the transition in the provenance and transport pathway of sediments in CSSM. The Huanghe sediments are characterized by higher smectite and the Changjiang sediments are characterized by higher illite. Korean river sediments contain more kaolinite and chlorite than those of chinese rivers. Korean river sediments have higher Al, Fe, K concentraion than Chinese river sediments and Chinese rivers have higher Ca, Mg, Na than those of Korean rivers. Therefore, clay minerals and major elements can be a useful indicator for provenance. Based on our results, CSSM can be divided into three sediment units. Unit 3, which corresponds to the lowstand stage, is interpreted that sediments from Huanghe were supplied to the study area by coastal or tidal currents. Unit 2, which corresponds to the transgressive stage, is interpreted to have a weaker Huanghe effect and a stronger Changjiang and Korean rivers effect. Unit 1, which corresponds to the highstand stage when the sea level is the same as present and current circulation system is formed, is interpreted that sediments from Changjiang and Korean rivers are supplied to the research area through the current.

• 한국해양학회지
• /
• v.28 no.1
• /
• pp.72-78
• /
• 1993

Sediment grain size was analysed and compared for standard solids and sediment samples using two different methods; SediGraph and MasterSizer. SediGraph results on sediment samples appeared as finer than those of MasterSizer, and the difference is great especially for biogenic siliceous ooze. The difference is maybe due to the following different points in two methods; pretreatment procedure, sample concentration, detachability on fine grains (about 1 um), and detection principle on nonspherical grains.

• Proceedings of the Korean Society of Computer Information Conference
• /
• 2012.07a
• /
• pp.33-34
• /
• 2012

토석류 퇴적 모델은 토석류에 의한 피해지 예측을 위해 그 효용성이 입증된 모델이지만 이를 이용하기 위해서는 몇 가지 파라미터를 필요로 한다. 파라미터를 자동으로 추정하기 위한 방법은 여러 가지가 있지만 토석류에 의한 피해지 예측을 위한 데이터는 충분히 양을 확보하기가 어려우므로 기존의 학습 기법을 적용하는데 어려움이 있다. 본 논문에서는 인공 신경망을 학습시키는 과정에서 기존 샘플로부터 의사 샘플을 생성하고 이를 학습에 사용함으로써 보다 안정적인 학습이 가능한 의사 샘플 신경망을 제안하였다. 제안한 의사 샘플 신경망은 해공간을 평탄화시킴으로써 잘못된 국부 최적해에 빠질 확률을 줄여주고 따라서 보다 안정적인 파라미터 추정이 가능하다는 사실을 실험을 통해 확인할 수 있다.