• Journal of the Korean Geographical Society
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• v.39 no.3
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• pp.425-443
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• 2004

Fluvial terraces is poorly developed along Bukhan River in Central Korea. Altitude from riverbed of T1 terraces are 18-29m, T2 terraces 2539m, respectively. Rubification index of T2 is 0.66, T1 is 0.54, and thickness of gravel weathering rind on gneiss of T2 are 14.0mm, granites of T2 are $\infty$, gneiss of T1 are 5.0mm and granites of T2 are 8.0mm, because weathering in deposits of T2 terraces, older than T1, is severer than T1 terraces. Since deposits in T2 have more active and longer weathering than T1, SiO$_2$/Al$_2$O$_3$ is 3.32 in T2 and 4.06 in T1, and SiO$_2$/R$_2$O$_3$ is 2.64 in T2 and 3.19 in T1. CIA(Chemical Index of Alteration) is 87.85％ in T2 and 85.88％ in T1. Kaolinite and halloysite are founded in deposits of T2 indicating high weathering, and are founded gibbsite made tv eluviation of kaolinite. However, deposits of T1 have no kaolinite, and are found plagioclase, weak mineral in weathering process. Comparing to previous researches by estimated age as altitude from riverbed, rubification index, thickness of gravel weathering rind, element contents and mineral composition, forming age of T2 terraces in Bukhan River are estimated in marine oxygen isotope stage 6 (130-190ka), and T1 terraces are marine oxygen isotope stage 4(59-74ka).

• Journal of the Korean Geographical Society
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• v.37 no.3
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• pp.222-236
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• 2002

The Osip-cheon river flowing on the east side of the Taeback mts. has formed river terraces on the several heights along the middle- and downstream. The river terraces are classified into 5 climatic ones and 7 thalassostatic ones. The thalassostatic ones are found to the height of 145-l50m level at 20-30m intervals. These vertical distribution is caused by the continuous uplift and periodical rise and fall of the sea-level. The high higher surfaces among the thalassostatic ones are the highest among those of Korea. The chronologies of the terraces are correlated to the marine oxygen isotope stages : The thalassostatic terraces on the level of 40 m.a.s.l. are to the stage 7, 70 m.a.s.l.. to the stage 9, 90 m.a.s.l. to the stage 9, 110 m.a.s.1. to the stage 11 and those of 150 m.a.s.1. to the stage 15 among the Interglacial Ages. The landuses and geomorphic landscapes of the Samchok area are chracteristic, because the karst landforms, such as doline and uvala, are developed on the surfaces of the middle-, the higher- and the high higher surfaces of river terrace.

• Journal of the Korean association of regional geographers
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• v.10 no.1
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• pp.177-191
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• 2004

Monitoring has been done for the shingle beach in Hagdong Beach in Geojesi, City during the seven month period. The shingle beach has been found to go through the cyclic change according to the tidal schedule. The typhoon Rusa in year 2002 affected whole beach face. Sea wall, constructed to protect the village along the beach, aggravates the situation, since it cut off the supply of shingle from the marine terrace, upon which village was built. Concrete walls along the streams also diminish the supply of shingles from the mountains. To protect the shingle beach and encourage the sustainable eco-tourism long-term monitoring on sediment budget is necessary.

• Journal of The Geomorphological Association of Korea
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• v.25 no.3
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• pp.57-70
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• 2018

This study restores onshore paleo-shoreline records and establishes the nature and strain rate of neotectonism by investigating the existence and formative age of paleo-coastal sediments emerged around Sacheon-si in the Southern part of the Korean peninsula. As a result, paleo-sand bars representing 5m of the paleo-shoreline from high tide level are formed in Sacheon-si, and the formation age of these is confirmed as MIS 5c at approximately 100,000 year BP through rock surface luminescence dating to rounded gravels in paleo-sand bars. Although it is difficult to establish the uplift rate of crust precisely due to incomplete restoration of sea level records during the last interglacial stage, the uplift rate along the Southern coast of the peninsula was assumed approximately 0.72 lower than the Eastern coast during the late Quaternary in comparison to the 1st marine terrace along the Eastern coast.

• Korean Journal of Soil Science and Fertilizer
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• v.45 no.5
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• pp.738-743
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• 2012

Topographic conditions of agricultural fields work as a important factor to identify different soil properties. This study was conducted to investigate the selected soil chemical properties and the concentrations of heavy metals, Cd, Cr, Pb, Cu, Ni, and Zn, in the paddy fields of different topographic areas at four year intervals from 1999 to 2011. Three-hundred soil sampling sites in the paddy fields were selected from the different topographic areas that were local valley and fans, fluvio-marine deposits, alluvial plains, and diluvial terraces. The mean values of soil pH ranged 5.7~5.8 that were within optimal range for rice cultivation. The mean values of other properties such as soil organic matter (SOM) content, the concentrations of exchangeable cations, $K^+$, $Ca^{2+}$, and $Mg^{2+}$, and available silicate concentration were lower or close to the optimal values, but the mean concentrations of available phosphorus were exceeded the range of optimal value, $80{\sim}120mg\;kg^{-1}$, in many paddy fields. In particular, The concentrations of available phosphorus in the paddy fields of local valley and fans, alluvial plains, and fluvio-marine plains were mostly declined. However, in diluvial terrace areas, the phosphorus concentrations unexpectedly increased; furthermore, they were significantly higher than those in other topographic areas. The mean concentrations of 0.1 M HCl-extractable heavy metals, Cd, Cr, Pb, Cu, Ni, and Zn, in the paddy fields were slightly and gradually declined during the study years, but the Pb concentrations were not statistically changed. In addition, the concentrations of heavy metals were widely ranged depending on the different sampling sites. Nevertheless, the concentrations of heavy metals were significantly lower than the levels of Soil Contamination Warning Standard (SCWS) for agricultural lands (1-region) presented in Soil Environment Conservation Law (SECL).

• Journal of the Korean Geographical Society
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• v.44 no.1
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• pp.31-55
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• 2009

This research aims 1) to characterize the spatial distribution of low relief landforms (plains) via analyses of a Digital Elevation Model (DEM), 2) to classify plains according to morphological and genetic similarity, and 3) to develop a model to explain forming processes of plains in the Korean peninsula. Plains can easily be separated from high relief mountaneous areas by analyzing the DEM. The overall morphological and locational characteristics of plains can be categorized into lava plains, fluvial-marine plains, erosional plains, intermontane basins, and higher ground plains. It is concluded that the characteristic of each plain type is decided by base-level changes caused by tectonic uplift and sea-level changes, and topological relationship of different rock types. Different plain types do not exist independently, but connected with each others along stream networks. The model developed is able to combine the morphological characteristics of plains with the channel network to conceptualize characteristics and development pathways of plains in the Korean Peninsula.

• The Journal of the Petrological Society of Korea
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• v.23 no.3
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• pp.261-272
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• 2014

Over the last three decades, advances in AMS (Accelerator Mass Spectrometry) and Noble Gas Mass Spectrometer make various application of terrestrial cosmogenic nuclides (CNs) to wide range of earth surface sciences possible. Dating techniques can be divided into three sub-approaches: simple surface exposure dating, depth-profile dating, and burial dating, depending on the condition of targeted surfaces. In terms of Korean landscape view, CNs dating can be applied to fluvial and marine terrace, alluvial fan, tectonic landform (fault scarp and faulted surfaces), debris landforms such as rock fall, talus, block field and stream, lacustrine and marine wave-cut platform, cave deposits, Pliocene basin fill and archaeological sites. In addition, in terms of lithology, the previous limit to quartz-rich rocks such as granite and gneiss can be expanded to volcanic and carbonate rocks with the help of recent advances in CNs analysis in those rocks.

• The Journal of the Petrological Society of Korea
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• v.25 no.3
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• pp.231-240
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• 2016

Three Quaternary faults have been revealed in marine terraces nearby the Homigot and the Gurongpo in the southeastern offshore of Korean Peninsula. The Hajung fault cuts the $4^{th}$ marine terraces and the Guman fault the $2^{nd}$, respectively. The Hajung fault strikes $N55^{\circ}$ to $45^{\circ}W$ and dips $40^{\circ}$ to $45^{\circ}NE$ with reverse-displacement of 180cm vertically. There are four sets of colluvial sediment strata that would be produced by faulting and indicate four times of fault movements during MIS 7 and MIS 5c. The Guman fault site consists of three sets of reverse faults that strike $N80^{\circ}E$ to $N70^{\circ}W$ and dip $25^{\circ}{\sim}35^{\circ}SE$ to $30^{\circ}SW$ with vertical displacement of 9~18 cm. The Guman faulting occurred during 80 ka (MIS 5a) to 71 ka (MIS 4) but it extends only to the lowest bed, the pebble sand bed, lay just on the unconformity, and not to the upper. Considering the attitude of the faults, we inferred that the Hajung fault was activated under the ENE-WSW compression during MIS 7 to MIS 5c and the Guman under N-S trending compression during MIS 5a. Using the OSL age dating results, we reconfirmed that the $2^{nd}$ terrace is correlated to MIS 5a and the $4^{th}$ terraces to MIS 7.

• Journal of the Korean association of regional geographers
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• v.18 no.4
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• pp.351-363
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• 2012

Although the Korean peninsula has been considered as a largely aseismic region compared with the surrounding high seismic areas such as North China and Japan, there are more than thirty Quaternary faults reported so far, which are mostly centered in the southeastern peninsula. Structural studies of active faults exposed in Yangnam-myeon of Gyeongju, SE Korea are largely interpreted to post date the late Quaternary, suggesting that the NE-trending reverse faults may result from the active stress regime in the peninsula. The prevailing present-day E-W $S_{Hmax}$ orientations in the peninsula are consistent with the nature of plate forcing stemming from the convergence between the Indo-Australian and Eurasian plates. It is clear that the Quaternary faults have been reactivated, although resolving more elaborate time intervals responsible for a future rupture remains a significant challenge. This study contributes to better assess many of potential seismic hazards in the study area, in particular, in terms of seismic stability for foundation of nuclear power plant.

• Journal of the Korean earth science society
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• v.43 no.6
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• pp.680-690
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• 2022

Tephrochronology uses regional tephra for age dating and stratigraphic correlations. Regional tephras are important in Quaternary geology and archaeology because they can be used as stratigraphic time-markers. In this review, identification and dating methods of tephra are summarized. In addition, the characteristics of regional tephras in terrestrial deposits of the Korean Peninsula are elaborated, and geological applications and limitations of the regional tephra layers are also discussed. So far, AT, Ata, and Kb-Ks tephra layers from Kyushu, Japan have been found in Pleistocene paleosol, marine terrace deposits, and lacustrine deposits in Korea. Also, although not officially confirmed, Aso-4 tephra is likely to occur in terrestrial deposits. The regional tephra layers are vital for dating, especially with regard to sediments over 50 ka beyond the range of radiocarbon dating, and for dating of active faults. Furthermore, it can provide important information for preparing countermeasures against volcanic disasters. However, in order to use the tephra layer geologically, it must be confirmed whether it is a primary deposit based on sedimentological study.