• Journal of Korean Society for Geospatial Information Science
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• v.23 no.3
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• pp.23-29
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• 2015

Due to the characteristics of landslide disasters including debris flow, the rapid speed to downward and difficulty to respond or evacuate from them, it is imperative to identify their potential hazards and prepare the reduction plans. However, the current landslide hazards generated by a variety of methods has been raised its accuracy because of the complexity of input data and their analyses, and the simplification of the landslide model. The main objective of this study is, therefore, to evaluate the preliminary landslide hazard based on the identification of geomorphological features. Especially, two methodologies based on the statistics of the directional data, Vector dispersion and Planarity analyses, are used to find some relationships between geomorphological characteristics and the landslide hazard. Results show that both methods well discriminate geomorphological features between stable and unstable domains in the landslide areas. Geomorphological features are closely related to the landslide hazard and it is imperative to maximize their characteristics by adapting multiple models rather than individual model only. In conclusions, the mechanism of landslide is not determined solely by a simple cause but the complex natural phenomenon caused by the interactions of the numerous factors and it is of primary importance to require additional researches for the outbreaking mechanism that are based on various methodologies.

• Journal of the Korean Geographical Society
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• v.39 no.4
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• pp.495-513
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• 2004

The shape of land surface work as a cradle for various environmental processes and human activities. As spatially distributed process modelings become increasing important in current research communities, a classification system that delineates land surface into characteristic geomorphological units is a pre-requisite for sustainable land use planning and management. Existing classification systems are either morphometric or generic, which have limitations to characterize continuous ecological processes over the landscape. A new classification system was developed to delineate the land surface into different geomorphological units from Digital Elevation Models(DEMs). This model assumes that there are pedo-geomorphological units in which distinct sets of hydrological, pedological, and consequent ecological processes occur. The classification system first divides the whole landsurface into eight soil-landscape units. Possible energy and material nows over the land surface were interpreted using a continuity equation of mass flow along the hillslope, and subsequently implemented in terrain analysis procedures. The developed models were tested at a 12$\textrm{km}^2$ area in Yangpyeong-gun, Kyeongi-do, Korea. The method proposed effectively delineates land surface into distinct pedo-geomorphological units, which identify the geomorphological characteristics over a large area at a low cost. The delineated landscape units mal provide a basic information for natural resource survey and environmental modeling practices.

• Journal of The Geomorphological Association of Korea
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• v.24 no.2
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• pp.41-49
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• 2017

From the results of the CIA analysis (A-CN-K and A-CNK-FM ternary diagram), we concluded that granitic grus experienced low chemical alteration and contains plenty of sandy material The chemical alteration of Geochang and Gajo Basin advanced further than that of Yeongju-Bonghwa basin, but does not come to spatial differentiation as Chuncheon Basin. The weathered mantles of inner hills in the basin exhibit very weak alteration, and there is little spatial differentiation of chemical alteration between footslope of mountains, footslope hills. Most of hills are still in incipient weathering stage and have plenty of sandy materials. Therefore the chemical characteristics of granitic hills in Geochang and Gajo basin show that granitic weathered mantles are not saprolite formed by alteration but may be just grus (sandy weathered mantles).

• Journal of The Geomorphological Association of Korea
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• v.23 no.2
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• pp.71-81
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• 2016

According to the result obtained by the CIA analysis(A-CN-K and A-CNK-FM ternary diagram), the chemical weathering of granitic grus in Chuncheon basin is too weak, thus calcium and sodium may not be dissolved sufficiently, but go as far as to be more progress than that of Yeongju-Bonghwa basin, Jeongeup, Nonsan and Namwon, common granitic grus in Korean Peninsula. Therefore the chemical characteristics of granitic hills in Chuncheon basin show that granitic weathered mantles are not saprolite formed by alteration while this may be true for guns(sandy weathered mantles). The weathered mantles of inner hills in the basin is slightly altered, footslope of mountains are more altered, and footslope hills are undergone some alteration. But their alteration doesn't show any advances to saprolite, and most of them are still in incipient weathering stage.

• Journal of the Korean Geotechnical Society
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• v.30 no.6
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• pp.61-68
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• 2014

The main objective of this study is to evaluate the preliminary landslide hazard based on the identification of geomorphological features, which are believed to be critical values in the initial state of landslides. Two methods, SINMAP and Planarity analyses, are used to simulate those characteristics where landslides are actually located. Results showed that both methods well discriminate geomorphic features between stable and unstable domains in the landslide areas. SINMAP analysis which is the consecutive model considering external factors like infiltration identifies the landslide hazard especially for debris flow type landslides better than plararity analysis focusing on a specific area. This analysis combined with other methods dealing with specific characteristics of geomorphological feature, the accurate landslide hazard will be evaluated.

• Journal of The Geomorphological Association of Korea
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• v.24 no.3
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• pp.149-159
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• 2017

Coastal dunes have many environmental and ecological socio-economic importances; various human activities, however, have impaired their structures and functions over the years. In 2016, environmental survey on coastal sand dune was carried out to report the present status and update the coastal sand dune list in 2001. This research analyzed the survey data in terms of geomorphological and socio-economic aspects. A list of the 189 coastal sand dune and information was updated by province. A 36.5% reduction in coastal sand dune area have been identified for using agricultural land, development area since the approximately 1940-50s. Development area in coastal sand dune covered small area as 5%, the use intensity was relatively hard. Furthermore, the difference by province also showed. Approximately 80% of the development area was concentrated in 20% of total sand dune several sand dune. It is generally accepted that coastal sand dunes were exposed high development pressure. However the result means that the general brief dose not apply for all sand dune. Therefore, characteristics of each sand dune should be analyzed and concerned the diverse management plans.

• Journal of The Geomorphological Association of Korea
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• v.23 no.3
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• pp.67-78
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• 2016

Soil carbon(C) is an essential property for characterizing soil quality. Understanding spatial patterns of soil C is particularly limited for mountain areas. This study aims to predict the spatial pattern of soil C using terrain analysis in a steep mountainous area. Specifically, model performances and prediction uncertainties were investigated based on the number of resampling repetitions. Further, important predictors for soil C were also identified. Finally, the spatial distribution of uncertainty was analyzed. A total of 91 soil samples were collected via conditioned latin hypercube sampling and a digital soil C map was developed using support vector regression which is one of the powerful machine learning methods. Results showed that there were no distinct differences of model performances depending on the number of repetitions except for 10-fold cross validation. For soil C, elevation and surface curvature were selected as important predictors by recursive feature elimination. Soil C showed higher values in higher elevation and concave slopes. The spatial pattern of soil C might possibly reflect lateral movement of water and materials along the surface configuration of the study area. The higher values of uncertainty in higher elevation and concave slopes might be related to geomorphological characteristics of the research area and the sampling design. This study is believed to provide a better understanding of the relationship between geomorphology and soil C in the mountainous ecosystem.

• Journal of the Korean Geographical Society
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• v.49 no.5
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• pp.656-674
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• 2014

The objective of this study was to examine the distinctiveness and generality of landforms of the Korean peninsula, and further discover geomorphological principle that can be applied to land and environmental management in Korea. The research targeted East Asia and Korea, with terrain analysis conducted at a continental scale, national scale, and regional scale sequentially. East Asia displays complicated characteristics and evolutionary history of geotectonics, but exhibits distinct northeast-southwest geomorphological structure and connectivity at the continental level. While the Korean peninsula follows this pattern on a continental scale, it also features NNW-SSE direction (Nangrim and Taebaek Mountains) geomorphological connectivity that intersects at a right angle. From a national perspective, the Korean peninsula hosts the most diverse geomorphological features within East Asia. It does not have a high average altitude, but has relatively high slope angle and intricate topographical distribution in comparison to neighboring areas. While the mountains and plains of the Korean peninsula display a smooth connection, geomorphologically similar areas such as Shikhote-Alin, Huanan in China, and Japan have clear characteristics that divide the mountains and plains. Despite the distinctiveness and diversity that appear in East Asian topography on the regional scale, the connectivity that links the top of mountain (hill) to stream is identical among all areas as a general rule. It is collectively considering the connectivity and the geomorphological and ecological processes that arise within this connectivity that will serve as the focal point for sustainable landscape management.

• Journal of The Geomorphological Association of Korea
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• v.17 no.2
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• pp.63-76
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• 2010

The Jangdo wetland is located on a very gentle slope of the mountain area in Daejangdo island, Shinan-gun, Korea, in which the area of the watershed is estimated at 147,000 m². The wetland has been regarded as a peat bog without any sedimentological evidence. This study was conducted to analyze the geomorphological and sedimentological characteristics of the wetland. The geographic information system (GIS) was used to analyze the drainage system, and field surveys were conducted to measure the range and depth of wetland deposits. The grain size analysis, organic matter determination, elements analysis and radiocarbon dating were performed on samples from the wetland. As a result, the wetland deposits were about 30 cm deep on average, the mean grain sizes ranged from 50 to 500 μm, and the average C/N ratio was 11.5. The portion of organic matter it contained was only 5~26%, which did not satisfy the peat standards. The radiocarbon ages from the wetland deposits range 180±50 ¹⁴C yr BP to modern, which indicated that natural and anthropogenic interferences including agricultural activities have continuously happened. We conclude that the Jangdo wetland is still in its infancy, not a steady state, so that it could be very sensitive to a small disturbance.

• Journal of the Korean Association of Geographic Information Studies
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• v.20 no.2
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• pp.75-88
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• 2017

This study analyzed wind flows based on spatial and geomorphological characteristics of Daegu Metropolitan City. A three-stage analysis was performed, starting with a comparison of meteorological relationships between local wind direction (synoptic wind) and local wind flow. In the second stage the study area was subdivided into districts and suburban districts to analyze the relative change of local wind flow. In stage three, the formation of wind corridor for local wind flow, wind flow for the entire urban space, and spatial relationships between flows were verified comparatively using KLAM_21. Three results are notable, the first of which is a low correlation between synoptic wind of a region, and local wind, flow in terms of meteorology. Secondly, observations of local wind flow at five downtown districts and two suburban districts showed that there were diverse wind directions at each measurement point. This indicates that the spatial and geomorphological characteristics of areas neighboring the measurement points could affect the local wind flow. Thirdly, verifying the results analyzed using KLAM_21, compared to Atomatic Weather System(AWS) measurement data, confirmed the reliability of the numerical modelling analysis. It was determined that local wind flow in a city performs a spatial function and role in ameliorating the urban heat island phenomena. This indicates that, when an urban planning project is designed, the urban heat island phenomena could be ameliorated effectively and sustainably if local wind flow caused by immediate spatial and geomorphological characteristics is confirmed systematically and techniques are intentionally applied to connect the flows spatially within areas where urban heat islands occur.