• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.38 no.6
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• pp.697-705
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• 2020

This paper deals with an analysis of crustal movement for the sourthern part of Korean peninsula using GNSS (Global Navigation Satellite System) data. An earthquake of more than 5.0 occurred in the southeastern region of the Korean Peninsula, and it is necessary to evaluate the risk of earthquakes in various ways.In order to reveal long-term tectonic movement patten in Pohang and Gyeongju provinces, we derived crustal movement parameters related with elastic theory. We used GAMIT/GLOBK for analyzing seven-year interval GNSS data of CORS (Continuously Operating Reference Stations). The azimuth of velocity vectors trended generally about 110° with an mean magnitude of 31mm/yr.The main characteristics of the strain change for seven-year in Korea obtaind from our study. Direction of the principal axis of the maximum compression is ENE-WSW as a whole, through there are some exceptions. The mean rate of the maximum shear strain change is (0.11±0.07)μ/yr, that is approximately one third that of Chubu district, Central Japan. Taking into account our results, the mean rate of maximum shear in southern part of Korean peninsula is considered as reasonable. The mean azimuth of principal strain is about (85.4°±26.8°). There are some exceptions of azimuth because the average azimuth differ from the left and right side in Yangsan fault which are about (73.2°±21.5°) and (105.2°±17.0°) respectively, It is noteworthy that the high seismicity areas in the southern part of Korea peninsula almost coincides with the area of large strain rate. As a conclusion, it could be stated that the our study represents the characteristics of crustal deformation in the southern part of peninsula, and contributes to the researches on earthquake disaster management.

• Journal of the korean society of oceanography
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• v.31 no.1
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• pp.23-31
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• 1996

The thermo-haline front frequently observed near the southwestern tip of Korean Peninsula is successfully modeled using a simple model. The front is formed by the wind-driven advection of local cooled water to the southern warm area which is kept warm by large heat advection of the Tsushima Current. The front thus locates north of the Tsushima Current which runs approximately along the isobaths in the east-west direction.

• Korean Journal of Plant Taxonomy
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• v.50 no.2
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• pp.239-246
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• 2020

Carex nakasimae Ohwi (Cyperaceae) is an endemic species on the Korean peninsula. This study reports a new locality of the species, updating the distribution map. A new population of the species was found during field surveys in 2014 in a small swamp in Haman-gun, Gyeongsangnam-do province, located in the southeastern part of the Korean peninsula. In the flowering and fruiting periods of the species, the population is associated with ca. 91 vascular plant taxa from 40 families. To conserve the endemic species, maintaining the habitat is critical. Furthermore, taxonomic and phylogenetic positions of the species should be clarified to establish biological conservation strategies for the rare, endemic C. nakasimae.

• Journal of Environmental Science International
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• v.12 no.9
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• pp.943-948
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• 2003

Variation of the polar front in the East Sea is studied using temperature and dissolved oxygen data obtained from Japan Meteorological Agency from 1972 to 1999. Variation of the polar front in the East Sea has a close relation to the variation of the Tsushima Warm Current (TWC). When the TWC spreads widely in the East Sea, polar front moves northward. The spatial variation of the polar front is greater in the southwestern area of the East Sea and the northern area of Tsugaru Strait where the variation of the TWC's distribution area is greater than those in others of the East Sea. Hence, in the southeastern area of the East Sea, that is, between near Noto peninsula and Tsugaru Strait, the spatial variation of the polar front is not so wide as in the southwestern area because the flow of TWC is stable.

• The Korean Journal of Quaternary Research
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• v.18 no.1 s.22
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• pp.41-46
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• 2004

The fluvia(thalassostatic) terraces have been developed among the lower Yeongsan river, near the southwestern coastal region of Korean peninsula. These thalassostatic terraces could be classified into 3 surface, i. e., Yeongsan 32m, 18m, and 10m surface, in desending order, according to the relative heights from the river floor. Yeongsan 32m, 18m and 10m surfaces were corresponded to the mMT3, mLT1 and mLT2 surfaces of Choi(2003), respectively. It was revealed that the mLT1 surface was the marine terraces which had been formed in the Last Interglacial culmination period(oxygen isotope stage 5e) in the southeastern coast of Korean peninsula.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.38-38
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• 2012

The East Asia (EA) region including China, Taiwan, Japan, and Korea are especially vulnerable to hydrometerological extremes during the boreal summer (June-September). This study, therefore, pursued an exploratory analysis to improve better understanding of the potential impacts of the two types of PJ patterns on WNP Tropical cyclone (TC) activities and TC-induced extreme moisture fluxes over Korea's five major river basins. This study shows that during positive PJ years, the large-scale atmospheric environments are more favorable for the TC activities than those in negative PJ years. During positive PJ year, it is found that there are weaker wind shear, stronger rising motion, as well as large relative humidity over the Korean peninsula (KP) compared to negative PJ years. As a result, TCs making landfall are more exhibited over the southeastern portions of South Korea. Despite the relatively modest sample size, we expect that insights and results presented here will be useful for developing a critical support system for the effective reduction and mitigation of TC-caused disasters, as well as for water supply management in coupled human and natural systems.

• Journal of The Geomorphological Association of Korea
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• v.25 no.4
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• pp.63-75
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• 2018

The lower marine terrace 1 and 2 surfaces distributed between Ulsan and Pohang coast in the southeastern coast of the Korean penninsula have been correlated with MIS 5e and 5a (or 5c) by amino acid dates, 14C dates, wide-spread tephra correlation and pollen analysis respectively. In this study, to test the reliability of the OSL method for the estimation of the numerical burial age of marine sediment deposits, we analyzed the samples from the marine terraces which have been known as typical marine terraces formed during MIS 5e and MIS 5a in the above-mentioned coast. The burial ages of the marine deposit of the lower marine terrace 1 and 2, with paleoshoreline altitudes of 18m to 19m and 10m to 11m respectively, both showed about the same age of 60 ka BP. The lower marine terraces 1 and 2, however, were divided into two terrace surfaces by a clear terrace cliff. Besides, the OSL dates of the lower and upper parts of the lower marine terrace 2 of the Bonggil coast showed the reversed burial ages. In the lower marine terrace 1 of the Sanhari coast, almost the same burial ages were derived from both the lower part (marine rounded gravel layer) and the upper part (terrestrial angular gravel layer) of the terrace deposit. Therefore, at the present time, judging from only the OSL dates measured in this study, it could be argued that the OSL method is not the best for the estimation of forming periods of the lower marine terraces 1 and 2 and their classification.

• Economic and Environmental Geology
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• v.39 no.4 s.179
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• pp.507-524
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• 2006

3-D seismic tomographic inversion is applied to investigation on velocity structure in and near Korean Peninsula. Firstly, it is applied to the region in southeastern Korean Peninsula. According to the results low-velocity zone seems to be clearly appeared in the so called Gyeongsang sedimentary basin and high-velocity zone is shown at the section of 7.5 km depth it implies the inclusion of plutonic rocks at the sedimentary basin. At the depth about $20{\sim}30$ km existence of low-velocity zone seems to be related with the development of Yangsan fault system. Secondly it is applied to the region not only in Korean Peninsula but also East Sea using data from both Korean Peninsula and Japan Islands. Accorging to the results, subduction zone starting from eastern part of Japan seems to be extended to the region beneath the East Sea.

• The Journal of the Petrological Society of Korea
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• v.13 no.2
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• pp.64-80
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• 2004

The Miocene volcanic rocks in the Eoil Basin, which is one of the pull-apart basins in the southeastern Korean Peninsula, are bimodal in composition: felsic (67.2-70.5wt.% SiO$_2$) and mafic(49.3-55.2wt.% SiO$_2$). The bimodal volcanic activities in the basin appear to be closely associated with the basin development. The volcanic rocks are intercalated with thick Files of sedimentary sequence. They show evidence of magma mixing. which has produced mafic and felsic volcanic rocks. We are able to identify the petrographic characteristics (disequilibrium phenocryst assemblages) of the volcanic rocks that were mixed. In basaltic lava, phenocrysts of olivine and orthopyroxene coexist with corroded quartz phenocryst. Dacitic to rhyolitic welded ash-flow tuff contains phenocrysts of clinopyroxene and orthopyroxene. It suggests that phenocryst disequilibrium have been affected and mixed by magmas, which have different compositions.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.210-221
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• 1998

In the period from the year 1500 to 1980. at least 14 large earthquake with epicenters in the northeastern China and Yellow Sea were felt or destructive in the Korean Peninsula. The most sigmificant events among them were the 1668 July 25 Tancheng earthquake of mamnitude 8.5, and the 1975 Feb. 4 Haicheng earthquake of magnitude 7.3. The Haicheng earthquake of the year 1975 in am extraordinary one among those occurred in the northeastern China in the 20th century in the sense the Shake of the event affected all over the Korean Peninsula. The tremor was felt even at the southeastern tip of the Korea and northern part of Kyushu 700km far away from the epicenter. In order to see the variation and trend of the effect of the Haicheng earthquake on the Korean Peninsula, the two data sets of the northern and southern parts of the peninsula were merged into one combined data set. The spatial variation of intensity shows smooth decrease from the value 4 of the northwestern region near the source to the value 1 of the Cheju Island and Kjushu. However, there are four regions of locally high intensity value. They are the region along downstream of Abrok(Yalu) River with intensity 5, the region around Shinpo of intensity 4, the area comprising Seoul and Chuncheon Cities of intensity 4, and Pohang-Pusan area of intensity 3. We suppose that there might be three types of possible mechanisms. The first one is concerned with the lateral inhomogeneity of velocity in the crust caused by wide distribution of relatively fractured rock. The second one is related with reflections of surface waves caused by the crestal thinning effect at border regions of the Peninsular in contact with the Ulleung Basin and the Japan Basin. The third possibility is local site effect caused by thick Tertiary or Quaternary rocks and soil layers.