• Journal of the Korean earth science society
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• v.36 no.7
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• pp.617-631
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• 2015

The Sesong Formation, mixed carbonate-siliciclastic deposits of late Middle Cambrian (Series 3) to Furongian in age, in the Taebaeksan Basin shows the Steptoean Positive Carbon Isotope Excursion (SPICE) with the ${\delta}^{13}C$ values ranging from 1.14 to 2.81‰ in the approximately 15-m-thick stratigraphic interval. The SPICE in the Sesong Formation occurs in the lower part of the Paibian Stage which contains trilobite biozones of the Fenghuangella laevis Zone, Prochuangia mansuyi Zone and the lower part of the Chuangia Zone. The Sesong Formation is composed of six lithofacies including laminated mudstone, nodular shale, laminated sandstone, massive sandstone, limestone conglomerate, and limestone-shale couplet facies. The Sesong Formation is known to have been deposited in the outer shelf below storm wave base. The SPICE occurs in the stratigraphic interval associated with highstand systems tract, correlative conformity and transgressive systems tract of the Sesong Formation. The peak carbon isotope value in the SPICE may coincide with the correlative conformity formed by relative sea-level fall. The occurrence of the SPICE in the Sesong Formation suggests that the SPICE can be used as a tool of global correlation for the successions of mixed carbonate-siliciclastics which lack fossils.

• The Journal of the Petrological Society of Korea
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• v.23 no.4
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• pp.311-324
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• 2014

The Hongjeom formation of the Pyeongan Supergroup in the Munkyeong coalfield mainly consists of metapsammite and metapelites. Metampelites occur as slate preserving chloritoid+chlorite+muscovite and andalusite+biotite+chlorite+muscovite mineral assemblages. Chloritoid and andalusite occur as porphyroblast, and the matrix composed of fine-grained micas. Metamorphic P-T conditions for these mineral assemblages are $510-520^{\circ}C$ and 3.0-3.5kbar based on P-T pseudosection in $MnO-K_2O-FeO-MgO-Al_2O_3-SiO_2-H_2O(MnKFMASH)$ system and isopleth intersections of Fe/(Fe+Mg) ratios in chloritoid and chlorite. The medium temperature and low pressure metamorphism resulted from a higher geothermal gradient ($40-45^{\circ}C/km$) condition than that of burial metamorphism. The youngest (SHRIMP U-Pb age; ca. 327-310 Ma) detrital zircon grains from the Hongjeom formation display oscillatory zoning and relatively high Th/U ratio (0.60-1.12). Based on the previous sedimentary, paleontological, and geochronological studies in the Taebaeksan basin together with results of this study, we suggest that (1) initial deposition of the Hongjeom formation was contemporaneous with a magmatic activity in the provenance, (2) the Pyeongan Supergroup was deposited in an arc-related basin at an active continental margin during the Carboniferous to Permain, and (3) magmatic activities occurred repetitively in relatively short interval in the active continental margin had continuously supplied sediments to the basin.

• Journal of Environmental Policy
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• v.8 no.4
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• pp.25-36
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• 2009

The Total Pollutant Load Management System(TPLMS) in the Han River basin is being changed from a voluntary to a mandatory system. Accordingly, this study suggests directions and priorities for research that can support implementation of TPLMS through an objective approach that deploys gap analysis and analytic hierarchy processes (AHP). Gap analysis indicated that TPLMS in Korea is still focused on compliance with regulations, and that implementation of TPLMS is still in its early stage. Improvements are thus needed in flexibility and effectiveness, including introduction of emissions rights trading, and upgrading to a renewable emissions permit system. The AHP study indicated that R&D will need to proceed in parallel in multiple areas to improve systems and resolve scientific uncertainties. Balanced R&D will be needed in both the institutional and technical groups. Subgroup analysis indicated that developing a reasonable process to establish water quality management targets is of the highest priority in the institutional group. In the technical group, higher priority will need to be given to improving model reliability and developing innovative pollution load reduction technologies.

• Korean Journal of Agricultural and Forest Meteorology
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• v.18 no.4
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• pp.287-297
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• 2016

This study aims to identify the relationship between climatic factors and stand mean Diameter at Breast Height (DBH) for two major tree species; Pinus densiflora and Quercus mongolica in Andong-dam basin. Forest variables such as age, diameter distribution and number of trees per hectare from the $5^{th}$ and $6^{th}$ National Forest Inventory data were used to develop a DBH estimation model. Climate data were collected from six meteorological observatory station and twelve Automatic Weather System provided by Korea Meteorological Administration to produce interpolated daily average temperature map with Inverse Distance Weighting (IDW) method. Andong-dam basin reflects rugged mountainous terrain, so temperature were adjusted by lapse rate based correction. As a result, predictions of model were consistent with the previous studies; that the rising temperature is negatively related to the growth of Pinus densiflora whereas opposing trend is observed for Quercus mongolica.

• Journal of Korea Water Resources Association
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• v.44 no.1
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• pp.51-64
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• 2011

The objective of this study is to develop a continuous rainfall-runoff model for flood prediction on a large-scale basin. For this study, the hourly surface runoff estimation method based on the variable retention parameter and runoff curve number is developed. This model is composed that the soil moisture to continuous rainfall can be simulated with applying the hydrologic components to the continuous equation for soil moisture. The runoff can be simulated by linking the hydrologic components with the storage function model continuously. The runoff simulation to large basins can be performed by using channel storage function model. Nakdong river basin is selected as the study area. The model accuracy is evaluated at the 8 measurement sites during flood season in 2006 (calibration period) and 2007~2008 (verification period). The calibrated model simulations are well fitted to the observations. Nash and Sutcliffe model efficiencies in the calibration and verification periods exist in the range of 0.81 to 0.95 and 0.70 to 0.94, respectively. The behavior of soil moisture depending on the rainfall and the annual loadings of simulated hydrologic components are rational. From this results, continuous rainfall-runoff model developed in this study can be used to predict the discharge on large basins.

• Geophysics and Geophysical Exploration
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• v.24 no.3
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• pp.78-88
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• 2021

Owing to the abnormal weather conditions due to global warming, carbon capture and storage (CCS) technology has attracted global attention as a countermeasure to reduce CO₂ emissions. In the Pohang CCS demonstration project in South Korea, 100 tons of CO₂ were successfully injected into the subsurface CO₂ storage in early 2017. However, after the 2017 Pohang earthquake, the Pohang CCS demonstration project was suspended due to an increase in social concerns about the safety of the CCS project. In this study, to reconfirm the structural suitability of the CO₂ storage site in the Pohang Basin, we employed seismic imaging based on reverse-time migration (RTM) to analyze small-scale ocean-bottom seismic data, which have not been utilized in previous studies. Compared with seismic images using marine streamer data, the continuity of subsurface layers in the RTM image using the ocean-bottom seismic data is improved. Based on the obtained subsurface image, we discuss the structural suitability of the Pohang CO₂ storage site.

• Journal of the Korean Geotechnical Society
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• v.25 no.6
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• pp.17-29
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• 2009

There has been an increase in the investigation of deep sea sediments with a consequent increase in the amount of energy required to undertake these investigations. The geotechnical characteristics of Ulleung Basin sediment are explored by using depressurized specimens following methane production tests carried out on pressured core samples obtained at 2,100 m water depth and 110 m below sea floor. Geotechnical index tests, X-ray diffraction, and scanning electron microscope are conducted to identify the geotechnical index parameters, clay mineralogy, chemical composition, and microstructure of the sediments. Compressibility, and elastic and electromagnetic wave parameters are investigated for two samples by using a multi sensing instrumented oedometer cell. The strength chatracteristics are obtained by the direct shear tests. The dominant clay minerals are mostly kaolinite, illite, chlorite, and calcite. The SEM shows a well-developed flocculated structure of the microfossil. Void ratio, electrical resistivity, real permittivity, conductivity, and shear wave velocity show bi-linear behavior with the effective vertical stress: as the vertical effective stress increases. The friction angle obtained by the direct shear test is about $21^{\circ}$, which is similar to the value observed in the Ulleung Basin sediments. This study shows that the understanding of the behavior acting on the diatomaceous marine sediment is important because it often maintains the useful energy resources such as gas hydrate and so will be the new engineering field in the next generation.

• Journal of Korean Society for Atmospheric Environment
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• v.28 no.5
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• pp.581-594
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• 2012

The goal of this study is to investigate the effects of the chemical lateral boundary conditions (CLBCs) on Community Multi-scale Air Quality (CMAQ) simulations of tropospheric ozone for East Asia. We developed linking tool to produce CLBCs of CMAQ from Goddard Earth Observing System-Chemistry (GEOS-Chem) as a global chemistry model. We examined two CLBCs: the fixed CLBC in CMAQ (CLBC-CMAQ) and the CLBC from GEOS-Chem (CLBC-GEOS). The ozone fields by CMAQ simulation with these two CLBCs were compared to Tropospheric Emission Spectrometer (TES) satellite data, ozonesonde and surface measurements for May and August in 2008. The results with CLBC-GOES showed a better tropospheric ozone prediction than that with CLBC-CMAQ. The CLBC-GEOS simulation led to the increase in tropospheric ozone concentrations throughout the model domain, due to be influenced high ozone concentrations of upper troposphere and near inflow western and northern boundaries. Statistical evaluations also showed that the CLBC-GEOS case had better results of both the index of Agreement (IOA) and mean normalized bias. In the case of IOA, the CLBC-GEOS simulation was improved about 0.3 compared to CLBC-CMAQ due to the better predictions for high ozone concentrations in upper troposphere.

• Korean Journal of Environmental Agriculture
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• v.34 no.4
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• pp.294-302
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• 2015

BACKGROUND: Chemical accidents have increased owing to chemical usage, human error and technical failures during the last decades. Many countries have organized supervisory authorities in charge of enforcing related rules and regulations to prevent chemical accidents. A very important part in chemical accidents has been coping with comprehensive first aid tool. Therefore, the present research has provided information with the initial applications concern to the rapid analysis of hazardous material using instruments in vehicle of field mode after chemical accidents. METHODS AND RESULTS: Mobile measurement vehicle was manufactured to obtain information regarding field assessments of chemical accidents. This vehicle was equipped with four instruments including gas chromatography with mass spectrometry (GC/MS), Fourier Transform Infrared Spectroscopy (FT-IR), Ion Chromatography (IC), and UV/Vis spectrometer (UV) to analyses of accident preparedness substances, volatile compounds, and organic gases. Moreover, this work was the first examined the evaluation of applicability for analysis instruments using 20 chemicals in various accident preparedness substances (GC/MS; 6 chemicals, FT-IR; 2 chemicals, IC; 11 chemicals, and UV; 1 chemical) and their calibration curves were obtained with high linearity ( r ² > 0.991). Our results were observed the advantage of the high chromatographic peak capacity, fast analysis, and good sensitivity as well as resolution. CONCLUSION: When chemical accidents are occurred, the posted measurement vehicle may be utilized as tool an effective for qualitative and quantitative information in the scene of an accident owing to the rapid analysis of hazardous material.

• Economic and Environmental Geology
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• v.45 no.6
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• pp.661-672
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• 2012

Lab scale experiments to investigate the dissolution reaction among supercritical $CO_2$-sandstone-groundwater by using sandstones from Gyeongsang basin were performed. High pressurized cell system (100 bar and $50^{\circ}C$) was designed to create supercritical $CO_2$ in the cell, simulating the sub-surface $CO_2$ storage site. The first-order dissolution coefficient ($k_d$) of the sandstone was calculated by measuring the change of the weight of thin section or the concentration of ions dissolved in groundwater at the reaction time intervals. For 30 days of the supercritical $CO_2$-sandstone-groundwater reaction, physical properties of sandstone cores in Gyeongsang basin were measured to investigate the effect of supercritical $CO_2$ on the sandstone. The weight change of sandstone cores was also measured to calculate the dissolution coefficient and the dissolution time of 1 g per unit area (1 $cm^2$) of each sandstone was quantitatively predicted. For the experiment using thin sections, mass of $Ca^{2+}$ and $Na^+$ dissolved in groundwater increased, suggesting that plagioclase and calcite of the sandstone would be significantly dissolved when it contacts with supercritical $CO_2$ and groundwater at $CO_2$ sequestration sites. 0.66% of the original thin sec-tion mass for the sandstone were dissolved after 30 days reaction. The average porosity for C sandstones was 8.183% and it increased to 8.789% after 30 days of the reaction. The average dry density, seismic velocity, and 1-D compression strength of sandstones decreased and these results were dependent on the porosity increase by the dissolution during the reaction. By using the first-order dissolution coefficient, the average time to dissolve 1 g of B and C sandstones per unit area (1 $cm^2$) was calculated as 1,532 years and 329 years, respectively. From results, it was investigated that the physical property change of sandstones at Gyeongsang basin would rapidly occur when the supercritical $CO_2$ was injected into $CO_2$ sequestration sites.