The Journal of the Petrological Society of Korea, 2005
This study was intended to elucidate the petrography and geochemical characteristics of the Someo... more This study was intended to elucidate the petrography and geochemical characteristics of the Someori Basalt in the Udo monogenetic volcano, eastern Jeju Island. The Someori basalts consist of plagioclase, olivine, orthopyroxene, clinopyroxene and ilmenite. The Someori basalts are plotted into subalkali rock series on the TAS diagram, and belong to tholeiitic basalts in the diagram of alkali index against to Al₂O₃ contents. The basalts belong to tholeiitic rock series, having normative quartz (less than 3.9%) + hypersthene + diopside.
Southeastern part of Korean peninsula was one of the largest Cretaceous intermediate to silicic v... more Southeastern part of Korean peninsula was one of the largest Cretaceous intermediate to silicic volcanic fields in the northwest Pacific. Many volcanic complexes were formed in relation to voluminous ash-flow eruption. This paper discusses K-Ar age and cauldron structure of the Choijeongsan, Unmunsa and Jangsan volcanic complex which is located in the Yoocheon subbasin. The Choijeongsan volcanic complex is composed of the basement rock (sedimentary rocks), intra-caldera volcanics (andesite and dacite ash-flow tuff), ring-dikes (quartz porphyry, feldspar porphyry, granite porphyry and felsite) and central pluton (quartz-monzonite). The Choijeongsan cauldron measures 10×8 ㎞, is nested caldera-complexes in the Cheongdo caldera, which measures 28×28 ㎞ in diameter. The Unmunsa volcanic complex measures 33 by 25 ㎞ in diameter and stratigraphically consists of basement rocks (volcaniclastic sedimentary rocks and andesite tuff and lava), intracaldera volcanics (Unmunsa rhyolite: dacite to r...
The materials generating from volcanic eruption are volcanic gases, lavas and pyroclastic materia... more The materials generating from volcanic eruption are volcanic gases, lavas and pyroclastic materials. Volcanic ash which has small-grain size (< 2 mm in diameter) can be moved easily and disperse widely, thus it may affect to communities across hundreds of square kilometers. The impacts from volcanic ash fall on people, structures, equipments, plants and livestock largely depend on ash thickness. According to increasing ash thickness, the intensity and area of damage may increase and affect significant damages not to human health but also to infrastructures. To reduce the impacts from volcanic ash fall, we have to establish the guidances about the nature and extent of the hazard and prepare the actions to increase abilities of communities to manage hazard. Although we don't have any experience caused by volcanic ash fall during and after volcanic eruption, we need to prepare the impacts of volcanic ash fall for future eruption in the areas surrounding Korea.
The Journal of the Petrological Society of Korea, 2005
This study was intended to elucidate the petrography and geochemical characteristics of the Someo... more This study was intended to elucidate the petrography and geochemical characteristics of the Someori Basalt in the Udo monogenetic volcano, eastern Jeju Island. The Someori basalts consist of plagioclase, olivine, orthopyroxene, clinopyroxene and ilmenite. The Someori basalts are plotted into subalkali rock series on the TAS diagram, and belong to tholeiitic basalts in the diagram of alkali index against to Al₂O₃ contents. The basalts belong to tholeiitic rock series, having normative quartz (less than 3.9%) + hypersthene + diopside.
Southeastern part of Korean peninsula was one of the largest Cretaceous intermediate to silicic v... more Southeastern part of Korean peninsula was one of the largest Cretaceous intermediate to silicic volcanic fields in the northwest Pacific. Many volcanic complexes were formed in relation to voluminous ash-flow eruption. This paper discusses K-Ar age and cauldron structure of the Choijeongsan, Unmunsa and Jangsan volcanic complex which is located in the Yoocheon subbasin. The Choijeongsan volcanic complex is composed of the basement rock (sedimentary rocks), intra-caldera volcanics (andesite and dacite ash-flow tuff), ring-dikes (quartz porphyry, feldspar porphyry, granite porphyry and felsite) and central pluton (quartz-monzonite). The Choijeongsan cauldron measures 10×8 ㎞, is nested caldera-complexes in the Cheongdo caldera, which measures 28×28 ㎞ in diameter. The Unmunsa volcanic complex measures 33 by 25 ㎞ in diameter and stratigraphically consists of basement rocks (volcaniclastic sedimentary rocks and andesite tuff and lava), intracaldera volcanics (Unmunsa rhyolite: dacite to r...
The materials generating from volcanic eruption are volcanic gases, lavas and pyroclastic materia... more The materials generating from volcanic eruption are volcanic gases, lavas and pyroclastic materials. Volcanic ash which has small-grain size (< 2 mm in diameter) can be moved easily and disperse widely, thus it may affect to communities across hundreds of square kilometers. The impacts from volcanic ash fall on people, structures, equipments, plants and livestock largely depend on ash thickness. According to increasing ash thickness, the intensity and area of damage may increase and affect significant damages not to human health but also to infrastructures. To reduce the impacts from volcanic ash fall, we have to establish the guidances about the nature and extent of the hazard and prepare the actions to increase abilities of communities to manage hazard. Although we don't have any experience caused by volcanic ash fall during and after volcanic eruption, we need to prepare the impacts of volcanic ash fall for future eruption in the areas surrounding Korea.
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