• Journal of The Geomorphological Association of Korea
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• v.28 no.4
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• pp.15-30
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• 2021

This study analyzed the changes in land-cover and sedimentary environment before and after flooding through drone images and sediment analysis for the Seomjin River Chimsil Wetland. The results showed that the area of some land-covers such as sand bar, grass, and trees were continuously changed. The acidity level of the sediments in the Seomjin River Chimsil Wetland was weakened gradually by flooding and EC was also decreased. The levels of organic matter, effective phosphoric acid, and CEC, however, were fluctuating depending on branches, which seems to be the result of landization as new sedimentary environment was developed and vegetation was settled after the flood. Average mean size of river sediments was found to be fine sand, and it exhibited various particle size characteristics from granule to medium silt depending on the location. As the sedimentary environment changed due to the effects of floods and typhoons, the particles were granulated or grain refined depending on the position. In the Seomjin River Chimsil Wetland, there were factors that could interfere with geomorphic development and sedimentary environment, contamination sources in and around the wetland, and natural threat factors. Therefore, in this study, a conservation and management plan was proposed to remove these threat factors and to preserve the scarcity, naturalness, and dynamics of Seomjin River Chimsil Wetland.

• Journal of The Geomorphological Association of Korea
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• v.25 no.1
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• pp.31-45
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• 2018

This study investigated the characteristics of sedimentary environment changes across a tidal flat in Gagyeongju of Anmyeondo Island. We performed a spatio-temporal analysis on the grain sizes composition of sediments and micro-landform changes during the winter from 2013 to 2016. The results showed that erosion was a dominant processthroughout the study flat, reducing the surface elevation even by 1 m around the upper sand flat. As a consequence, headlands have formed in the entire region of Gagyeongju village. In addition, erosion quickly progressed along the low-lying subtidal zone and tide way and, in contrast, sedimentation progressed in the mid-elevation tidal flat. We posit that a jetty, which had been constructed as a pier facility on the eastern part of the study area, interfered with the flow of tidal current, thereby enhancing these erosional processes. This is because such interference can block the supply of fine-textured sediments from the nearby Cheonsu Bay and therefore reduce surface elevation. According to the surface sediment analysis, the sediments were categorized into 7 sedimentary facies, and generally displayed a high ratio of silt and clay. The result of time-series analysis (2012-2013) showed that the sediments on the tidal flat became fine-grained, and that sorting became worse. However, the sediments on the subtidal zone, embayment and along inside of the jetty tended to be coarse-grained. In conclusion, the tidal flat microlandform change in the study area was caused by a disruption in the seawater circulation due to the jittery construction within the tidal flat, which had a direct effect on erosional and sedimentary environment processes.

• Journal of The Geomorphological Association of Korea
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• v.18 no.4
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• pp.59-78
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• 2011

In this study, the tidal flat research history of South Korea was organized by type and period. South Korea's tidal flat research history was largely divided into four fields: sediment research of tidal flat, research using satellite imagery, research on the Quaternary environment change and tidal flats, and ecological research on tidal flats. The comprehensive review of the South Korean tidal flat research history showed that tidal flats had been researched on since the period of Japanese colonial period, but most of the past studies were related to fisheries. Then, in the 1960s, the studies started to focus on the reclaimed land created through reclamation projects. The research on tidal flats from a geomorphological perspective fundamentally started in the 1970s, and the importance of tidal flats became more widely known in the 1980s. Most of the studies then were about the sedimentary environment and the form of landform, the ecosystem, and morphological changes. Since the 2000s, research has been carried out on satellite imagery data together with field survey, to continuously monitor the changes in the sedimentary facies of tidal flats, and in the sedimentary environment. There have been many academic studies on the geographic field of tidal flats, but the research performance on tidal flats in terms of geomorphology is still a blue ocean that has been touched by only a few. Therefore, it is hoped that various studies on Korean tidal flats will be conducted by geomorphologists in the future, and that such area will be established as an important field of study in geomorphology.

• Journal of The Geomorphological Association of Korea
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• v.17 no.4
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• pp.29-40
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• 2010

The Palgye Plain, located in Chilgok, Buk-gu, Daegu-si, is a floodplain by Palgye-River rising from Mt. Ga one of the mountains in Ring Typed Mountains of Mt. Palgong. The geomorphic surfaces in the study area can be divided into the natural levee, back marsh and confluent fan, and the natural levee and fan have been used as important regions of human activities since the Bronze Age. The alluvium sediments of Palgye-River can be subdivided into the bedrocks, lower gravel deposits, lower sandy deposits, lower silty deposits, upper sand and gravel deposits, and upper silty deposits from the bottom according to the formative ages. The lower gravel deposits correlated to the last glacial stage and the rest to Holocene, respectively. Confluent fans were also formed during the last glacial stage. Moreover, The landscape with land use after 20C was changed to apartment area due to civilization differently from which reflected the characteristics of geomorphic surfaces in the past.

• Journal of The Geomorphological Association of Korea
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• v.23 no.2
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• pp.83-93
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• 2016

Using a Quaternary sediment sampled from the Gwnahju-cheon various organic carbon analysis have been accomplished. The result helped us to figure out how climate environment has changed through at that time. The analysis outcome, except the analysis of upper section(range of 0 to 50 cm depth), showed that the climate was generally warm and humid at that time. However, even in this result, the climate environment was slight differences, it can be divided into four periods. Period I is from $3,880{\pm}30yr\;BP$ to $3,030{\pm}70yr\;BP$, in which the climate was relatively warm and humid/dry slightly. Period II is from $3,030{\pm}70yr\;BP$ to $2,970{\pm}70yr\;BP$, in which the climate was relatively warmer than period I and the most humid among all period. Period III is from $2,970{\pm}30yr\;BP$ to $2,270{\pm}70yr\;BP$ and refers to the warmest among all periods and also relatively drier/more humid than period I. Period IV which is from $2,270{\pm}70yr\;BP$ to $2,170{\pm}110yr\;BP$ represents the coolest and driest climate compare to other periods, although there is a high possibility of disturbance caused by cultivation activities.

• Journal of The Geomorphological Association of Korea
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• v.20 no.3
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• pp.109-118
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• 2013

The purpose of this study is to clarify the optimum locational environment of Neolithic Age and Bronze Age dwelling sites in Yeongjong-do, Incheon in terms of geographical characteristics. To make this possible, the micro-landform location environment of individual dwelling sites has been analyzed targeting 145 dwelling sites of Neolithic Age and 47 dwelling sites of Bronze Age in which quantitative analysis is possible among the dwelling sites verified in the investigation area until now. As a result, the micro-landform of hills where Neolithic Age and Bronze Age dwelling sites are crowded the most has been determined as the upper side hollow (64 dwelling sites, 44.1%) and the crest slope (39 dwelling sites, 83%), respectively. This means that the optimum locational environment of dwelling sites has been changed as the times have progressed from Neolithic Age to Bronze Age in the investigation area and the location of micro-landform of hills also where dwelling sites are located also has relatively moved up a little seen in terms of geographical perspective.

• Journal of The Geomorphological Association of Korea
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• v.20 no.3
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• pp.1-14
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• 2013

This study aims to investigate the formation and sedimentary environment including formative period, grain composition and climate change from loess-paleosol sequence deposited on a gravel bed of river terrace in the Jincheon Basin, Chungbuk Province. The Jincheon section consists downward of a surface layer, loess-paleosol sequence, transitional layer I, transitional layer II and gravel bed. It can be suggested from the OSL age dating that the sequence was deposited during MIS 6 to 4. The sequence can be divided into four horizons based on the variation in the magnetic susceptibility values. Grain size analysis reveals that the sequence indicates similar properties of grain size to loess deposits in Korea and especially, the Y values in the sequence are lower than those in the loess and paleosol horizons in the Chinese Loess Plateau and similar to those in the Red Clay in the Chinese Loess Plateau and Xiashu loess in the lower reaches of the Yangtze River. These Y values in the sequence can be attributed to the remote source and/or experience of intensive weathering process after deposition in the Korean Peninsula.

• Journal of The Geomorphological Association of Korea
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• v.25 no.4
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• pp.37-47
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• 2018

Coastal sand dunes have been regarded as natural defenses to protect hinterland from disasters such as storm surge and typhoons. However, many dunes are not well-deserved in South Korea because of imprudent land development or inappropriate measures after coastal erosion. Lately, beach nourishment and dune reinforcement are emphasized as the effective and environmentally sustainable solution for the coastal protection. They are regarded good strategies to keep landscapes for a time, with little side effects. However, there is little knowledge on the construction methods including proper design and time plans for the best results.In addition, the effects of dune reinforcement in the field should be tested.In thisstudy, we performed sand filling in an eroded dune scarp and surveyed topographic changes in the beach-dune system, which is located along Dasa-ri coast, Chungnam Province, South Korea. Using a network RTK-GPS and drone-based aerial photographs, we analyzed the temporal and spatial changes in the area, before and after the reinforcement. As a result, the dune reinforcement seems to be helpful to mitigates the coastal erosion and to prevent the coastline retreat at least for one year.

• Journal of The Geomorphological Association of Korea
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• v.19 no.1
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• pp.41-56
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• 2012

The purpose of this study is to look into the location environment of prehistoric and ancient remains (hereinafter referred as remains) in Daejeon Area. For the purpose of this, out of remains reported in investigation areas so far with the object of remains (total 22 places) of New Stone Age -Proto Three Kingdom period, geographical and Geomorphological analysis was conducted. The results are like the following. Most of the remains are distributed over hills especially flat surface - semi-gentle slope of hills. The bed rocks of the remains (21 places, about 95%) are composed of double-mica granite. The remains (19 places, 86%) retain 'the 1st-2nd small scale river and '5th or higher medium scale river'within comparatively short distance at the same time. The average altitude of remains is 71m and most remains are located over the altitude of 50 - 90m. The average gradient of hillslop where the remains are located is $6.7^{\circ}$ and the remains (15 places, 71%) are located over the gradient of about $0-15^{\circ}$. And the tendency that the higher the gradient of remains the smaller the number of remains was confirmed. From the above, it is judged that the inhabitants who lived in Daejeon Area at that time preferred hills with comparatively not high altitude and the earth's surface of low gradient and in addition they recognized water (river) as being important when they selected the location of settlement (or dwelling sites group).

• Journal of The Geomorphological Association of Korea
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• v.19 no.1
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• pp.109-121
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• 2012

Human responses, such as construction of levees, are a spatial representation of the place vulnerability which is induced by a geomorphic hazard like flooding. Human responses include all forms of human activities to reduce the place vulnerability and they seem to be related with reducing vulnerability rather than reducing geomorphic hazards. Diverse human responses to the perceived environment bring about changes in the place vulnerability. People respond spatially to their vulnerability of the place in diverse ways from their experience and perceived risk. Human responses have quantitative possibilities in predicting and modeling the place vulnerability. Building the model of a dynamic place vulnerability to the diverse geomorphic hazards requires basic maps of geomorphic processes and human responses in the region.