• Magazine of the Korean Society of Agricultural Engineers
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• v.42 no.3
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• pp.5-17
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• 2000

The story of route of wet-rice diffusion to Korean peninsular is so far known only piecemeal. It is however commonly agreed that wet-rice technology may have spread the western coastal area in Korea from the lower and middle reaches of the yangzi river in China and to the Shandong peninsular and Bohai Bay region and was then transmitted overland to the area in Korea. Recently excavated three prehistoric paddy fields in Korea provide crucial evidence that helps to solve many of the important problems associated with technological diffusion. Research on the paddy field system and irrigation technology of prehistoric wet-rice has been so far especially productive in Japanese archaeology. Judging from the fact that the Yayoi wet-rice agricultural technology in Japan was transmitted by the Korean Strait from the southern part of Korea it is assumed that people in both regions may have practiced the same technology in prehistoric time. This paper examines three prehistoric paddy fields system(the Majon-ri site the Kwanchang-ri site and the Mujon-dong site) in relation to those of japanese data. The conclusions are as follows ; First early wet-rice agriculture in korea was limited by the level of technology and the size of labour. Secondly the location of field itself was restricted to the lower land and valley bottom area. Thirdly the layout of channel and field network is not very much different from the modern paddy field system.

• Journal of the Korean Geographical Society
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• v.31 no.3
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• pp.613-629
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• 1996

River terraces of glacial and interglacial periods are most developed in the Ungcheon River, midwestern coastal region of south Korea. Among these terraces, interglacial river terraces correspond to the thalassostatic terraces of eastern coastal region of Korea. Thus the former shoreline altitudes of the coastal region around Ungcheon River can be estimated by using relative heights of these interglacial thalassostatic terraces of Ungcheon River The former shoreline altitudes estimated from interglacial thalassostatic terraces of Ungcheon River are 80m, 50${\sim}$60m, 40${\sim}$45m, 30m, 25m(?), 15${\sim}$20m, and 10m. These estimates are almost identical with those of Quaternary sea levels of eastern coastal region. Among the above estimates of Ungcheon River, the former shoreline altituded of 15~20m and 10m correspond to the ancient sea levels of $\pm$18m and $\pm$10m of eastern coastal region which were injudged as the last interglacial culmination period and late warmer period of the last interglacia(5e and 5a substages of oxygen isotope stage), respectively. Therefore there is a possibility that the rest of the above former shoreline altitudes of the coastal region aroune Jngcheon River also correspond to those of eastern coastal region. On the basis of the above possibility it can be proposed that the eastern and western coastal region of Korean Peninsula have undergone tectonic uplift of equall amount since the middle Quaternary Period.

• Korean Journal of Soil Science and Fertilizer
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• v.16 no.2
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• pp.106-111
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• 1983

As calculation of R factor value in the Universal Soil-Loss Equation is tedious, a new simple method (IAS Index) to approximate the R factor value is proposed. Although the several methods have been tested to get R value, no one fits our conditions. IAS Index is simply calculated by summing up the amount of rainfall over two months with maximum $EI_{30}$ values. The Index is highly correlated to $EI_{30}$ value in western part of peninsular. The difference is less than 10% between $EI_{30}$ value and IAS Index. Therefore, R factor can be estimated from IAS index, summing up the rainfall amount of June and August in this region. However, IAS Index works poorly in other region, especially, eastern coastal side. The large difference may be partly due to side distribution of $EI_{30}$ value, which means no special $EI_{30}$ peaks during heavy rainy months. In this case, IAS Index is not applicable directly.

• Journal of the Korean Geographical Society
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• v.42 no.3 s.120
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• pp.368-387
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• 2007

In order to explain geomorphological characteristics of the Korean Peninsula, it is necessary to understand the spatial distribution of tectonic movements and its causes. Even though geomorphological elements which might have been formed by tectonic movements(e.g. tilted overall landform, erosion surface, river terrace, marine terraces, etc.) have long been considered as main geomorphological research topics in Korea, the knowledge on the spatial distribution of tectonic movement is still limited. This research aims to identify the spatial distributions of tectonic movement via sequential analyses of Digital Elevation Model(DEM). This paper first developed a set of terrain analysis techniques derived from theoretical interrelationships between tectonic uplifts and landsurface denudation processes. The terrain analyses used in this research assume that elevations along major drainage basin divides might preserve original landsurfaces(psuedo-landsuface) that were formed by tectonic movement with relatively little influence by denudation processes. Psuedo-landsurfaces derived from a DEM show clear spatial distribution patterns with distinct directional alignments. Lines connecting psuedo-landsufaces in a certain direction are defined as psuedo-landsurface axes, which are again categorized into two groups: the first is uplift psuedo-landsurface axes that indicate the axis of landmass uplift; and the second is denudational psuedo-landsurface axes that cross step-shaped pusedo-landsurfaces formed via surface denudation. In total, 13 axes of pusedo-landsurface are identified in the Korean Peninsula, which show distinct direction, length, and relative uplift rate. Judging from the distribution of psudo-landsurfaces and their axes, it is concluded that the Korean Peninsula ran be divided into four tectonic regions, which are named as the Northern Tectonic Region, Center Tectonic Region, Southern Tectonic Region, and East Sea Tectonic Region, respectively. The Northern Tectonic Region had experienced a regional uplift centered at the Kaema plateau, and the rate of uplift gradually decreased toward southern, western and eastern directions. The Center Tectonic Region shows an arch-shaped uplift. Its uplift rate is the highest along the East Sea and the rate decreases towards the Yellow sea. The Southern Tectonic Region shows an asymmetric uplift centered a line connecting Dukyu and Jiri Mountains in the middle of the region. The eastern side of the Southern Regions shows higher uplift rate than that of the western side. The East Sea Tectonic Region includes south-eastern coastal area of the peninsula and Gilju-Myeongchun Jigudae, which shows relatively recent tectonic movements in Korea. Since this research visualizes the spatial heterogeneity of long-term tenonic movement in the Korean peninsula, this would provide valuable basic information on long-term and regional differences of geomorphological evolutionary processes and regional geomorphological differences of the Korean Peninsula.