• Economic and Environmental Geology
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• v.54 no.2
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• pp.271-283
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• 2021

The Imjingang Belt in the middle-western Korean Peninsula has tectonically been correlated with the Permo-Triassic Qinling-Dabie-Sulu collisional belt between the North and South China cratons in terms of collisional tectonics. Within the belt, crustal-scale extensional ductile shear zones that were interpreted to be formed during collapsing stage with thrusts and folds were reported as evidence of collisional events by previous studies. In this study, we tried to understand the nature of deformation along the southern boundary of the belt in the Munsan area based on the interpretations of recently conducted structural analyses. To figure out the realistic geometry of the study area, the down-plunge projection was carried out based on the geometric relationships between structural elements from the detailed field investigation. We also conducted kinematic interpretations based on the observed shear sense indicators from the outcrops and the oriented thin-sections made from the mylonite samples. The prominent structures of the Munsan area are the regional-scale ENE-WSW striking thrust and the N-S trending map-scale folds, both in its hanging wall and footwall areas. Shear sense indicators suggest both eastward and westward vergence, showing opposite directions on each limb of the map-scale folds in the Munsan area. In addition, observed deformed microstructures from the biotite gneiss and the metasyenite of the Munsan area suggest that their deformation conditions are corresponding to the typical mid-crustal plastic deformation of the quartzofeldspathic metamorphic rocks. These microstructural results combined with the macro-scale structural interpretations suggest that the shear zones preserved in the Munsan area is mostly related to the development of the N-S trending map-scale folds that might be formed by flexural folding rather than the previously reported E-W trending crustal-scale extensional ductile shear zone by Permo-Triassic collision. These detailed examinations of the structures preserved in the Imjingang Belt can further contribute to solving the tectonic enigma of the Korean collisional orogen.

• Korean Journal of Weed Science
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• v.18 no.4
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• pp.356-363
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• 1998

In general weed vegetation analysis has been applied to the study of weed population shift. However, it is a limited tool for understanding a problem region and a specific weed species in a certain area. Recently GIS may be used as an important tool to solve this target or to conduct specific field analysis which enables to introduce a reasonable management strategy. Thus, the GIS study was carried out to understand an integrated weed population changes between 1981 and 1992 in Korea. The nationwide weed survey was performed through the whole rice paddy fields in 1981 and 1992. Weed occurrence was totally different over whole country based on these data. In 1981 a region with high weed occurrence was at western and central areas of Korea in terms of weed population density but this was changed into western and southern area in 1992. In both years there were high weed population density at Taean, Seosan county of Chungnam province in Korea. Thus, this particular area may be needed to introduce a special strategy to reduce weed population density and/or to control problem weed species.

• Journal of the Korean Association of Geographic Information Studies
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• v.19 no.2
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• pp.14-26
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• 2016

This study analyzed the correlation between the standardized precipitation index(SPI) and forest fire occurrences using monthly accumulative rainfall data since 1970 and regional fire occurrence data since 1991. To understand the relationship between the SPI and forest fire occurrences, the correlations among the SPI of nine main observatory weather stations including Seoul, number of fire occurrences, and log of fire occurrences were analyzed. We analyzed the correlation of SPI with fire occurrences in the 1990s and 2000s and found that in the 1990s, the SPI of 3 months showed high correlation in Gyeonggi, Gangwon, and Chungnam, while the SPI of 6 months showed high correlation in Chungbuk, and the SPI of 12 months showed high correlation in Gyeongnam, Gyenongbuk, Jeonnam, and Jeonbuk. In the 2000s, the SPI of 6 months showed high correlation with the fire frequency in Gyeonggi, Chungnam, Chungbuk, Jeonnam, and Jeonbuk, whereas the fire frequency in western Gangwon was highly correlated with the SPI of 3 months and, in eastern Gangwon, Gyeongnam, and Gyenongbuk, with the SPI of 1 month. In the 1990s, distinct differences in the drought condition between the SPI of 3 months and 12 months in the northern and southern regions of Korean Peninsula were found, whereas the differences in both the SPI of 1 month and 6 months were found in the Baekdudaegan region except western Gangwon since the 2000s. Therefore, this study suggests that we can develop a model to predict forest fire occurrences by applying the SPI of 1-month and 6-month data in the future.

• Parasites, Hosts and Diseases
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• v.35 no.3
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• pp.171-180
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• 1997

Studies on geographical distributions and relative population densities of the vector mites of tsutsugamushi disease were carried out in October 1996 at 12 locations of the mid south inland of the Korean peninsula, where chigger mites have been never studied. Of 177 field rodents and insectivores collected. 154 (87.0%) were Apodemus ngrarius. Total 25,707 chigger mites were collected and 14 species were identified. of which Leptotrombidium pnllidum was predominant (79.8%) and L. palpate the next (8.9%) . L. pallidum, the vector species, was widely distributed in all study areas, showing the highest density at Cho-o 2-dong, Sangju-si (chigger index 201.8), and the lowest at Tanwol-dong. Chungiu-si (chigger index 40.7) . The other vector species, L. scutellare was found only at the southern part of the study area such as Yobae and Mipyong, Kumrung gun and Vnsu , Kimchon-si. The northernmost areas of the L. scutellcre distribution were coincided with the areas where actual mean air temperature is above 10.0%. Among 157 A. ograrius sera tested, 48.3% was Karp, 1.7% william and 3.3% Kuroki. The rest of the sera were not able to determine the sexto-type because of the cross antigen-antibody reactions among the tested sero-types.

• Journal of the Korean Society of Food Science and Nutrition
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• v.41 no.6
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• pp.739-744
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• 2012

Cirsium japonicum (Gyonggido (GG), Gangwondo (GW), Jeollanamdo (JN) and Jejudo (JJ)) were investigated for their antioxidative components (total polyphenol and flavonoid contents) and their antioxidant activities (2,2-diphenyl-1-picrylhydrazyl) (DPPH), 2,2'-azinobis (3-ethyl-benzothiazoline-6-sulfonic acid) (ABTS), ferric reducing antioxidant power (FRAP) and reducing power). Analysis of antioxidative components and activities showed significant (p<0.05) differences across samples from various regions (GG, GW, JN, JJ). Amounts of total polyphenol and flavonoid contents were in the order of GG${\geq}$GW>JJ>JN (p<0.05). The results of the antioxidative activity test of Cirsium japonicum showed that GG and GW had higher activities compared to others (p<0.05). Therefore, the results of the antioxidative activity test (DPPH, ABTS, FRAP and reducing power) were correlated with total polyphenol and flavonoid contents values.

• Economic and Environmental Geology
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• v.37 no.5
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• pp.555-568
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• 2004

The demand of aggregate resources in Korea has been increased with a rapid economic growth since the 1980s. About 25% of the total aggregate production is derived from riverine aggregates, 20% to 25% from marine sands, 40% to 45% from crushed aggregate and the rest 5% to 15% from old fluvial deposits. The abundance of crushed coarse aggregates varies in the uniform distribution of country, but in general it can be concentrated in the most densely populated areas, five main cities. Typical rock types of the Korean crushed stones are classified as plutonic rocks of 27%, metamorphic rocks of 32%, sedimentary rocks and volcanic rocks of 18%, respectively. The most abundant coarse aggregate used in the country is obtained from granite (25% of total) and subordinately gneiss (20%), sandstone (10%) and andesite (10%). Although rock types using as dimension stone are only fifteen, those as aggregate amount up to twenty nine rocks. These rocks consist of plutonic rocks such as granite, syenite, diorite, aplite, porphyry, felsite. dike and volcanic rocks such as rhyolite, andesite, trachyte, basalt, tuff, volcanic breccia and metamorphic rocks such as gneiss, schist, phyllite, slate, meld-sandstone, quartzite, hornfels, calc-silicate rock, amphibolite. And sandstone, shale, mudstone, conglomerate, limestone, breccia, chert are main aggregate sources in tile sedimentary rocks. The abundance of plutonic rocks is the highest in Chungcheongbuk-do, and decreases as the order of Jeollabuk-do, Gangwon-do and Gyeonggi-do. In Jeollanam-do, volcanic aggregates occupy above 50%, on the contrary sedimentary aggregates are above 50% in Gyeongsangnam-do.

• Journal of Animal Science and Technology
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• v.54 no.4
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• pp.247-253
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• 2012

Ultrasound measures of back fat thickness (UBF), eye muscle area (UEMA) and marbling score (UMS) and carcass measures of carcass weight (CW), backfat thickness (BF), eye muscle area (EMA) and marbling score (MS) were available on 26,129 Hanwoo steers. Statistically significant differences by regions of the farms location and birth years-seasons for the steers taken ultrasound measures and their carcass measures (p<0.01) were found. Steers in Gyeonggi province showed the highest values in ultrasound measures and carcass traits except in BF compared to steers in the other provinces. Comparing between ultrasound and carcass measures, UBF was thicker in general than BF in all regions except in Daejeon city. UEMA was higher than EMA in all regions except in Gyeonggior in Jeju provinces. Especially, the difference in Jeonnam province between UEMA and EMA was $7cm^2$ while the differences between UMS and MS ranged from 0.9 to 2.26 depending on the regions of steers located. Steers born in spring showed greater ultrasound or carcass values than those born in autumn. However, carcass measures of steers born in autumn were greater than those born in spring, 2009 except MS. The pearson and residual correlations were 0.63 and 0.65 between UBF and BF, 0.31 and 0.32 between UEMA and EMA and 0.56 and 0.56 between UMS and MS, respectively.

• Journal of environmental and Sanitary engineering
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• v.11 no.1
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• pp.1-8
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• 1996

In the present study the sesamin and sesamol contents of the sesame extracts prepared from nine provinces in Korea were determined HPLC method. A comparative test was also carried out using the Villavecchia-suarez test, the red colored reaction for the sesamol and sesamol derivatives. The contents of sesamin and sesamol of the sesame oils from each area by the HPLC method were 0.57-0.78% and 0.010-0.023%, respectively, and the paralled results were obtained by the Villavecchia-suarez test and the HPLC method. The average content of the sesamin was $0.68{\pm}0.074%$ by the HPLC method and the average absorbance of the Villavecchia-suarez test was $0.56{\pm}0.034$. The contents of sesamol from sesame oil by the HPLC method and the Villavecchia-suarez test were so low that it was not possible to correlate with the sesamin contents. The contents of sesamol from the sesame oil produced in Kyeong-gi and Jeon-nam provinces were $0.010{\pm}0.002%$ and $0.023{\pm}0.004%$, respectively.

• Journal of Wetlands Research
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• v.22 no.4
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• pp.328-336
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• 2020

In this study, the soil characteristics of peat layer in Korea were analysed to predict new peat distribution areas in Taean, Chungcheongnam-do. The soil characteristics of peat distribution areas in Taean were compared with those in other areas in Korea. In Korea, peat researches were conducted in various regions, such as Taean in Chungcheongnam-do, Pyeongtaek in Gyeonggi Province, Gangneung in Gangwon-do, Ulsan, Iksan in Jeollabuk-do and Jangheung in Jeollanam-do. We summarized a) topographic distribution, b) deposition type, c) soil drainage classes, and d) soil suborder of previously studied area to determine criteria for prediction of peat distribution area. Through a case study, the type of peat layer distribution area in Taean were divided into two; (1) a) valley, b) co-alluvium, c) somewhat poorly drained, d) aqualfs and (2) a) marine plain, b) alluvium, c) very poorly drained, d) aquepts. A field survey was conducted to confirm the distribution of the actual peat layer. All peat layer were located within 10-km from the coastal line which is similar to previous studies, and the peat layer was characterized with pH 5, humic acid content of less than 15% and dark brown color. The new peat layer in Taean was deeper, thicker and less humificated than other studied areas.

• Korean Journal of Agricultural and Forest Meteorology
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• v.22 no.2
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• pp.92-101
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• 2020

To prevent and mitigate damage to farms due to heavy snowfall, snow weight information should be provided in addition to snow depth. This study reviews four formulae regarding snow density and weight used in extant studies and applies them in Suwon area to estimate snow weight in Korea. We investigated the observed snow depth of 94 meteorological stations and automatic weather stations (AWS) data over the past 30 years (1988-2017). Based on the spatial distribution of snow depth by area in Korea, much of the fresh snow cover, due to heavy snowfall, occurred in Jeollabuk-do and Gangwon-do. Record snowfalls occurred in Gyeongsangbuk-do and Gangwon-do. However, the most recent heavy snowfall in winter occurred in Gyeonggi-do, Gyeongsangbuk-do, and Jeollanam-do. This implies that even if the snow depth is high, there is no significant damage unless the snow weight is high. The estimation of snow weight in Suwon area yielded different results based on the calculation method of snow density. In general, high snow depth is associated with heavy snow weight. However, maximum snow weight and maximum snow depth do not necessarily occur on the same day. The result of this study can be utilized to estimate the snow weight at other locations in Korea and to carry out snow weight prediction based on a numerical model. Snow weight information is expected to aid in establishing standards for greenhouse design and to reduce the economic losses incurred by farms.