• Title/Summary/Keyword: Southeastern Korea

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Foraminiferal Characteristics in Mud Deposits of the Southeastern Margin of Korea (한국 남동 대륙주변부 니질대 표층퇴적물의 유공충 특성)

  • Woo, Han-Jun;Choi, Jae-Ung
    • Ocean and Polar Research
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    • v.28 no.2
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    • pp.67-78
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    • 2006
  • Six surface sediments from two offshore transects of Ulsan and Gampo, on the southeastern margin of Korea were taken for sediment and foraminiferal analyses. Sedimentary processes are dominated by reworking and resedimentation from storms in the area off Ulsan and hemipelagic suspension settling in the area off Gampo. Eighty-four foraminiferal species were identified in total assemblages, including 33species of living populations and 9 species of planktonic foraminifera. The characteristics of foraminifera showed differences of offshore environments between Ulsan and Gampo. The number of living species, species diversity and equitability in Gampo offshore area had higher values than those in Ulsan offshore area. However, planktonic/benthic(P/B) ratio showed higher in the Ulsan offshore area. The species diversity indices and P/B ratio indicated that environmental stability and surface-ocean productivity in the Gampo offshore area were relatively higher than the Ulsan offshore area. The difference of species compositions is useful for interpreting the paleoenvironments in mud deposits of the southeastern margin of Korea.

Analysis of the Trends of Supply and Demand of Aggregate in the Southeastern Region of South Korea (동남권 골재수급 및 시장 동향 분석)

  • Choi, Se-Jin;Kim, Young-Uk;Kim, Do-Bin
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2018.05a
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    • pp.324-325
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    • 2018
  • Recently, the supply and demand of aggregate in the Southeast region has been disrupted because supply of sea sand decreased due to discontinuation of collecting the EEZ aggregate in the southern sea. This study analyzed the Trends of Supply and Demand of Aggregate in the Southeastern Region of South Korea in order to find a solution these social problem.

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A Case Study on Sea Breeze Circulation and Ozone Concentration due to the Effect of Cold Water in the Southeastern Coastal Area of Korea (한국 남동연안의 냉수대 영향에 의한 해풍순환과 오존농도의 사례연구)

  • Ji, Hyo Eun;Lee, Soon-Hwan;Park, Changhyoun;Lee, Hwa Woon
    • Journal of Environmental Science International
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    • v.23 no.2
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    • pp.261-274
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    • 2014
  • This work investigates the relationship between the sea breeze circulation and ozone concentrations during cold water events in the southeastern coastal area of the Korean Peninsula, where coastal upwelling frequently occur. This analysis was performed based on the classification of two categories, such as cold water and non-cold water events, over the period of 2000-2009. The low air temperature ($0.5^{\circ}C$), low SST ($5^{\circ}C$) and the wind direction(southerly) are the features of the cold water events in the Southeastern coastal area. Moreover, ozone concentrations in the cases of the sea breeze circulation and cold water events were significantly lower (below 30 ppb) than those (70~100 ppb) in the non-clod water events, because of the low air temperature ($10{\sim}20^{\circ}C$) and high wind speed (3~5 m/s) around the southeastern coastal area.

A Study of Multiple Scattering Model by Analytic Method for Southeastern Korea (한반도 남동부지역의 해석적방법에 의한 다중산란모델 연구)

  • Chung, Tae-Woong
    • Geophysics and Geophysical Exploration
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    • v.14 no.3
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    • pp.242-248
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    • 2011
  • By applying analytic method to the uniform model, the intrinsic and scattering quality factor ($Q_i^{-1}$ and $Q_s^{-1}$) was separated for the southeastern part of Korean Peninsula. The Multiple Lapse Time Window Analysis method was used to fit theoretical values with observations obtained 759 earthquake data. While previous study for the Korean Peninsula showed very low $Q_i^{-1}$ and $Q_s^{-1}$ reflecting inactive seismicity, southeastern Korea exhibited relatively high $Q_i^{-1}$ and $Q_s^{-1}$ values interpreted as higher seismicity than the other region in the peninsula.

The southeastern region of the Vela SNR

  • Kim, Il-Joong;Seon, Kwang-Il;Min, Kyoung-Wook
    • The Bulletin of The Korean Astronomical Society
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    • v.35 no.2
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    • pp.69.2-69.2
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    • 2010
  • We investigate the southeastern region of the Vela supernova remnant (SNR) in the multi-wavelength domains. This region is quite interesting because it includes the bullet feature D/D´ and another SNR (the Vela Jr.). The C IV $\lambda\lambda1548$, 1551 emission-line morphologies obtained from the FIMS/SPEAR data show that there are several local peaks of C IV on the bullet D/D´ and the Vela Jr. SNR. This may provide clues to direct interaction between both SNRs. Also, we found that the southeastern side of the Vela is in direct contact with an H-alpha ring feature whose central source seems to be a B-type star, HD 76161. The C IV emission peaks along this contact boundary. We investigate this interacting region in detail.

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Characteristics of the Cenozoic crustal deformation in SE Korea and their tectonic implications (한반도 동남부 신생대 지각변형의 주요 특징과 지구조적 의의)

  • Son, Moon;Kim, Jong-Sun;Chong, Hye-Yoon;Lee, Yung-Hee;Kim, In-Soo
    • The Korean Journal of Petroleum Geology
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    • v.13 no.1
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    • pp.1-16
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    • 2007
  • The southeastern Korean Peninsula has experienced crustal multi-deformations according to changes of global tectonic setting during the Cenozoic. Characteristic features of the crustal deformations in relation to major Cenozoic tectonic events are summarized as follows. (1) Collision of Indian and Eurasian continents and abrupt change of movement direction of the Pacific plate (50${\sim}$43 Ma): The collision of Indian and Eurasian continents caused the eastward extrusion of East Asia block as a trench-rollback, and then the movement direction of the Pacific plate was abruptly changed from NNW to WNW. As a result, the strong suction-force along the plate boundary produced a tensional stress field trending EW or WNW-ESE in southeastern Korea, which resultantly induced the passive intrusion of NS or NNE trending mafic dike swarm. (2) Opening of the East Sea (25${\sim}$16 Ma): The NS or NNW-SSE trending opening of the East Sea generated a dextral shear stress regime trending NNW-SSE along the eastern coast line of the Korean Peninsula. As a result, pull-apart basins were developed in right bending and overstepping parts along major dextral strike slip faults trending NNW-SSE in southeastern Korea. The basins can be divided into two types on the basis of geometry and kinematics: Parallelogram-shaped basin (rhombochasm) and wedged-shaped basin (sphenochasm), respectively. In those times, the basins and adjacent basement blocks experienced clockwise rotation and northwestward tilting contemporaneously, and the basins often experienced a kind of propagating rifting from NE toward SE. At about 17Ma, the Yonil Tectonic Line, which is the westernmost border fault of the Miocene crustal deformation in southeastern Korea, began to move as a major dextral strike slip fault. (3) Clockwise rotation of southeastern Japan Island (about 15 Ma): The collision of the Izu-Bonin Arc and southeastern Japan Island, as a result of northward movement of the Philippine sea-plate, induced the clockwise rotation of southeastern Japan Island. The event caused the NW-SE compression in the Korea Strait as a tectonic inversion, which resultantly tenninated the basin extension and caused local counterclockwise rotation of blocks in southeastern Korea. (4) E-W compression in the East Asia (after about 5 Ma): Decreasing subduction angle of the Pacific plate and eastward movement of the Amurian plate have constructed the-top-to-west thrusts and become a major cause for earthquakes in southeastern Korea until the present time.

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Analysis of Response Spectra using Microearthquakes of Southeastern Korean Peninsula (한반도 남동부 미소지진을 이용한 응답스펙트럼 분석)

  • 김연중
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • 2000.10a
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    • pp.27-32
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    • 2000
  • Microearthquake records with magnitude 2.6~3.1 recorded in the southeastern part of the Korean peninsula during 1994~1998 are analyzed. Total of 42 records consisted of 12 events instrumented at 7 stations. The response spectra with the above data shows that the frequency range of the dominant response is about 10~25Hz and are compared with the standard response spectrum. The result implies that the characteristics of the microearthquake ground motion differ from those of standard response spectrum presented in US NRC Reg. Guide 1.60 especially at higher frequencies.

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Mineral Distribution in the Southeastern Yellow Sea Surface Sediments; KORDI Cruise Samples in 2010 (황해 남동부 표층 해양 퇴적물의 광물 분포; 2010년 한국해양연구원 탐사 시료)

  • Cho, Hyen-Goo;Kim, Soon-Oh;Yi, Hi-Il;Shin, Kyung-Hoon
    • Journal of the Mineralogical Society of Korea
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    • v.24 no.3
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    • pp.205-216
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    • 2011
  • Mineral compositions of 69 southeastern Yellow Sea surface sediments collected at the Korea Ocean Research and Development Institute (KORDI) cruise in 2010, were determined using the quantitative X-ray diffraction analysis. Southeastern Yellow Sea surface sediments are composed of major minerals (quartz 49.1%, plagioclase 13.0% and alkali feldspar 9.3%), clay minerals, calcite, and aragonite. Illite (9.4%) is the most abundant clay mineral, chlorite (4.6%) is the second, and kaolinite (0.8%) is few. Quartz and alkali feldspar contents are high in coarse-grained sediments, whereas amphibole and clay mineral contents are high in fine-grained sediments. Quartz, plagioclase, alkali feldspar, chlorite, and kaolinite contents are higher, and illite content is lower in mud zone 1 corresponding to south margin of Central Yellow Sea Mud than in mud zone 2, a part of Southeastern Yellow Sea Mud. Difference of mineral composition between two mud zone suggests that source of fine sediment may be different in two mud zone and Southeastern Yellow Sea Mud might be largely supplied from the Keum and Youngsan rivers in southern part of the west coast in the Korean Peninsula.

Seropositivity Rates of Strongyloides stercoralis Antibody in the Southeastern Region of Republic of Korea: A Single-Center Retrospective Study

  • Kim, Taehwa;Lim, Seungjin
    • Parasites, Hosts and Diseases
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    • v.60 no.3
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    • pp.181-185
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    • 2022
  • Strongyloides stercoralis infection is not endemic in the Republic of Korea (Korea) with a positivity rate of <1% in stool examination. However, there is a risk of hyperinfection in immunosuppressed individuals. It is necessary to determine the seropositivity of S. stercoralis antibodies in Korea. This study investigated the seropositivity of S. stercoralis antibodies in the southeastern area of Korea. From January 2019 to June 2021, serum samples were collected from participants who visited the study center in the southeastern region of Korea for routine health check-ups. We determined serum levels of specific anti-Strongyloides IgG antibodies in 834 samples by enzyme-linked immunosorbent assay. We observed that 92 samples (11.0%) tested showed a positive response. The age of the participants was 51±10.7 years, and 43.4% of them were men. The antibody positivity rate based on the location of the participants' residence were 12.3% (Gyoungsangnam-do), 10.2% (Busan), and 10.1% (Ulsan), respectively. Total eosinophil count was associated with positive test results (154.8±152.0 per mm3 versus 202.1±178.9 per mm3, P=0.006). Logistic regression analysis revealed that blood eosinophil count, age above 50 years, and residence in Sacheon were factors associated with the positive status of S. stercoralis antibody. Our finding suggests that it is necessary to test for S. stercoralis in actual clinical settings in Korea.