• Economic and Environmental Geology
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• v.53 no.6
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• pp.729-742
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• 2020

In this study, we analyze seabottom conditions and characteristics integrated with topographic data, seafloor mosaic, underwater images and orthophoto(drone) of soft-hard bottom area around the Sib-Ri rock in the northern shore of the East Sea(Gyeongpo Beach, Gangneung). We obtained field survey data around the Sib-Ri rock(about 600 m × 600 m). The Sib-Ri rock is formed by two exposed rocks and surrounding reef. The artificial reef zone made by about 200 ~ 300 structures is shown the western area of the Sib-Ri rock. The underwater rock region is extended from the southwestern area of the exposed the Sib-Ri rock with 9 ~ 11 m depth range. The most broad rocky seabottom area is located in the southwestren area of the Sib-Ri rock with 10 ~ 13 m depth range. The study area were classified into 4 types of seabottom environment based on the analysis of bathymetric data, seafloor mosaics, composition of sediments and images(underwater and drone). The underwater rock zones(Type I) are the most distributed area around the Sib-Ri Rock(about 600 m × 600 m). The soft seabottom area made by sediments layer showed 2 types(Type II: gS(gravelly Sand), Type III: S(Sand)) in the areas between underwater rock zones and western part of the Sib-Ri rock(toward Gyeongpo Beach). The artificial reef zone with a lot of structures is located in the western part of the Sib-Ri rock. Marine algae(about 6 species), Phylum porifera(about 2 species), Phylum echinodermata(about 3 species), Phylum mollusca(about 3 species) and Phylum chordata(about 2 species) are dominant faunal group of underwater image analysis area(about 10 m × 10 m) in the northwestern part of the Sib-Ri rock. The habitat of Phylym mollusca(Lottia dorsuosa, Septifer virgatus) and Phylum arthropoda(Pollicipes mitella, Chthamalus challengeri hoek) appears in the intertidal zone of the Sib-Ri rock. And it is possible to estimate the range and distribution of the habitat based on the integrated study of orthphoto(drone) and bathymetry data. The integrated visualization and mapping techniques using seafloor mosaic images, sediments analysis, underwater images, orthophoto(drone) and topographic data can provide and contribute to figure out the seabottom conditions and characteristics in the shore of the East Sea.

• Economic and Environmental Geology
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• v.57 no.5
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• pp.529-537
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• 2024

Mineral composition used to identify the sedimentary environment can be obtained through X-ray diffraction (XRD) analysis. However, due to time constraints for analyzing a large number of samples, a machine learning-based mineral composition analysis model was developed. This model demonstrated reasonable reliability for samples with usual compositions but showed poor performance for unusual samples. Consequently, a clustering model has recently been developed to classify the unusual samples, allowing experts to handle. The purpose of this study is to examine the applicability of the clustering model, developed using XRD data from the Ulleung Basin in previous study, using samples from different regions. Research data consist of intensity profile from XRD experiment and its mineral composition analysis for a total of 54 sediment samples from the Korea Plateau, located northwest of the Ulleung Basin. Because the intensity of samples in the Korea Plateau comprises 7,420 values (3.005-64.996°), differing from 3,100 values (3.01-64.99°) of samples in the Ulleung Basin, linear interpolation was used to align the input feature. Then, min-max scaler was applied to intensity profile for each sample to preserve the trend and peak ratio of the intensity. Applying the clustering model to the 54 preprocessed intensity profiles, 35 samples and 19 samples were classified into expert and machine learning groups, respectively. For machine learning group, false positive was zero among the 19 samples. This means that the clustering model can increase reliability in when mineral composition from machine learning model because unusual sample did not belong to the machine learning group. For the 35 samples in expert group, the 31 samples were classified as false negative (FN). It means that although machine learning model can properly analyze these samples, they were assigned to expert group. However, when these FN samples were analyzed using machine learning based composition analysis model, a high mean absolute error of 2.94% was observed. Therefore, it is reasonable that the samples were assigned to expert group.

• Economic and Environmental Geology
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• v.47 no.4
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• pp.441-453
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• 2014

Thermal and physical properties were measured on 206 Jurassic granite samples obtained from three boreholes in the central part of Korea. Thermal conductivity(${\lambda}$), thermal diffusivity(${\alpha}$), and specific heat(Cp) were measured in a laboratory; the average values are ${\lambda}$=2.813 W/mK, ${\alpha}=1.296mm^2/sec$, and Cp=0.816 J/gK, respectively. In addition, porosity(${\phi}$), and dry and saturated density(${\rho}$) were measured in the laboratory; the average values are ${\phi}$=0.01, ${\rho}(dry)=2.662g/cm^3$ and ${\rho}(saturated)=2.67g/cm^3$, respectively. Thermal diffusivity of 10 granite samples were measured with increasing temperature from $25^{\circ}C$ to $200^{\circ}C$. In this study, we found that thermal diffusivity at $200^{\circ}C$ is about 30% lower than thermal diffusivity at $25^{\circ}C$. In correlation analysis, thermal conductivity increases with increasing thermal diffusivity. However, thermal conductivity does not show good correlation with porosity and density. Consequently, we know that thermal conductivity of granite would be more influenced by mineral composition than by porosity. We also derived ${\rho}=-2.393{\times}{\phi}+2.705$ from density and porosity data. XRD and XRF analysis were performed to investigate effects of mineral and chemical composition on thermal conductivity. From those results, we found that thermal conductivity increases with increasing quartz and $SiO_2$, and decreases with increasing albite and $Al_2O_3$. Regression analysis using those mineral and chemical composition were carried out ; we found $K=0.0294V_{Quartz}+1.93$ for quartz, $K=0.237W_{SiO_2}-14.09$ for $SiO_2$, and $K=0.053W_{SiO_2}-0.476W_{Al_2O_3}+6.52$ for $SiO_2$ and $Al_2O_3$. Specific gravities were measured on 10 granite samples in the laboratory. The measured specific gravity depends on chemical compositions of granite. Therefore, specific gravity can be estimated by the felsic-mafic index(F) that is calculated from chemical composition. The estimated specific gravity ranges from 2.643 to 2.658. The average relative error between measured and estimated specific gravities is 0.677%.

• Economic and Environmental Geology
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• v.49 no.6
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• pp.459-467
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• 2016

Due to the limited areal space for installation, borehole heat exchangers (BHEs) at depths deeper than 300 m are considered for geothermal heating and cooling in the urban area. The deep vertical closed-loop BHEs are unconventional due to the depth and the range of the typical installation depth is between 100 and 200 m in Korea. The BHE in the study consists of 50A (outer diameter 50 mm, SDR 11) PE U-tube pipe in a 150 mm diameter borehole with the depth of 300 m. In order to compensate the buoyancy caused by the low density of PE pipe ($0.94{\sim}0.96g/cm^3$) in the borehole filled with ground water, 10 weight band sets (4.6 kg/set) were attached to the bottom of U-tube. A thermal response test (TRT) and fundamental basic surveys on the thermophysical characteristics of the ground were conducted. Ground temperature measures around $15^{\circ}C$ from the surface to 100 m, and the geothermal gradient represents $1.9^{\circ}C/100m$ below 100 m. The TRT was conducted for 48 hours with 17.5 kW heat injection, 28.65 l/min at a circulation fluid flow rate indicates an average temperature difference $8.9^{\circ}C$ between inlet and outlet circulation fluid. The estimated thermophysical parameters are 3.0 W/mk of ground thermal conductivity and 0.104 mk/W of borehole thermal resistance. In the stepwise evaluation of TRT, the ground thermal conductivity was calculated at the standard deviation of 0.16 after the initial 13 hours. The sensitivity analysis on the borehole thermal resistance was also conducted with respect to the PE pipe diameter and the thermal conductivity of backfill material. The borehole thermal resistivity slightly decreased with the increase of the two parameters.

• Economic and Environmental Geology
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• v.46 no.3
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• pp.235-246
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• 2013

The importance of R&D has been recognized around the world and Korean research funding has rapidly increased in recent years. As a results, interest in strategic R&D Investment is growing in both the public and private sectors. This study was carried out to find trends in the research projects of the KIGAM since the fiscal year of 1976. The KIGAM expended 1,193.3 billion won during the 36 years from the fiscal years of 1976 to 2011, which is 1,795.8 billion won calculated using the present value in 2011 at discount rate of 5%. R&D expenditure of KIGAM increased approximately 132.9 times from 885 million won in 1976 to 117,600 million won in 2011, and about 24.1 times from 4,882 million won in 1976, as calculated using the present value in 2011. The number of research projects increased about 6.75 times, from 28 projects in 1976 to 189 projects in 2011. Based on research trend analysis over the last 36 years, the percentage of research projects by research fields were as follows: mineral resources research, 39.5%; geologic environmental research, 28.8%; geological research, 15.6%; petroleum and marine research, 12.1%; and policy research, 3.1%. The percentage of the R&D budget dedicated to each type of research were as follows: mineral resources research, 33.1%; geologic environmental research, 25.6%; geological research, 22.8%; petroleum and marine research, 15.9%; and policy research, 2.1%. Allocation of R&D investment was determined by considering the governmental priority of such research, as well as which area were most promising. Based on the research projects trends within KIGAM and analyses of its R&D, we should build our R&D portfolio in the areas of geosciences and mineral resources.

• Economic and Environmental Geology
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• v.53 no.5
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• pp.597-608
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• 2020

Even after the Gyeongju earthquake and the Pohang earthquake, hundreds of aftershocks and micro-earthquakes are still occurring in the southeastern part of the Korean Peninsula. These phenomena mean that the stress is constantly working, implying that another huge earthquake may occur in the future. Therefore, the gravity field interpretation method was used to analyze the deep geological structure of the Pohang-Ulsan region in the southeastern Korean Peninsula. First, a gravity survey was performed to collect the insufficient data and to calculate the detailed Bouguer gravity anomaly in the study area. Based on the gravity anomaly data, the location, direction, and maximum depth of deep fault lines were analyzed using the inversion methods "Curvature analysis" and "Euler deconvolution method". As a result, it is interpreted that at least six fault lines(C1~C6) exist in deep depth. The deep fault line C1 is well correlated to the Yeonil Tectonic Line(YTL), suggesting that YTL is extended up to about 4000m deep. The deep fault line C2 consists of several segment faults and well correlated to the fault lines on the surface. Inferred fault lines C3, C4, and C5 have an NW-SE direction, which is parallel to the Ulsan fault. The deep fault line C6 has the direction of NE-SW, and it is interpreted that the eastern boundary fault of Eoil Basin is extended to the deep. Comparing the inferred fault lines with the distribution of micro-earthquakes, the location of the deep fault line C1 is well correlated to the hypocenter of micro-earthquakes. This implies that faults in deep depth are related to the recent earthquakes in the southeastern Korean Peninsula.

• Economic and Environmental Geology
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• v.53 no.5
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• pp.609-617
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• 2020

After introducing the industry 4.0 policy, Korean government announced 'Digital New Deal' and 'Green New Deal' as 'Korean New Deal' in 2020. We analyzed Korea Institute of Geoscience and Mineral Resources (KIGAM)'s research projects related to that policy and conducted markets analysis focused on Digital Twin and environmental monitoring technologies. Regarding 'Data Dam' policy, we suggested the digital geo-contents with Augmented Reality (AR) & Virtual Reality (VR) and the public geo-data collection & sharing system. It is necessary to expand and support the smart mining and digital oil fields research for '5th generation mobile communication (5G) and artificial intelligence (AI) convergence into all industries' policy. Korean government is suggesting downtown 3D maps for 'Digital Twin' policy. KIGAM can provide 3D geological maps and Internet of Things (IoT) systems for social overhead capital (SOC) management. 'Green New Deal' proposed developing technologies for green industries including resource circulation, Carbon Capture Utilization and Storage (CCUS), and electric & hydrogen vehicles. KIGAM has carried out related research projects and currently conducts research on domestic energy storage minerals. Oil and gas industries are presented as representative applications of digital twin. Many progress is made in mining automation and digital mapping and Digital Twin Earth (DTE) is a emerging research subject. The emerging research subjects are deeply related to data analysis, simulation, AI, and the IoT, therefore KIGAM should collaborate with sensors and computing software & system companies.

• Economic and Environmental Geology
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• v.51 no.2
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• pp.185-201
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• 2018

Nuclear power plants(NPP) are constructed and operated to ensure safety against natural disasters and man-made disasters in all processes including site selection, site survey, design, construction, and operation. This paper will introduce a series of efforts conducted in Korea Hydro and Nuclear Power Co. Ltd., to assure the safety of nuclear power plant against earthquakes and other natural hazards. In particular, the present status of the earthquake, fault, and slope safety monitoring system for nuclear power plants is introduced. A earthquake observatory network for the NPP sites has been built up for nuclear safety and providing adequate seismic design standards for NPP sites by monitoring seismicity in and around NPPs since 1999. The Eupcheon Fault Monitoring System, composed of a strainmeter, seismometer, creepmeter, Global Positioning System, and groundwater meter, was installed to assess the safety of the Wolsung Nuclear Power Plant against earthquakes by monitoring the short- and long-term behavioral characteristics of the Eupcheon fault. Through the analysis of measured data, it was verified that the Eupcheon fault is a relatively stable fault that is not affected by earthquakes occurring around the southeastern part of the Korean peninsula. In addition, it was confirmed that the fault monitoring system could be very useful for seismic safety analysis and earthquake prediction study on the fault. K-SLOPE System for systematic slope monitoring was successfully developed for monitoring of the slope at nuclear power plants. Several kinds of monitoring devices including an inclinometer, tiltmeter, tension-wire, and precipitation gauge were installed on the NPP slope. A macro deformation analysis using terrestrial LiDAR (Light Detection And Ranging) was performed for overall slope deformation evaluation.

• Economic and Environmental Geology
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• v.50 no.2
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• pp.171-180
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• 2017

This study performed the analysis on the volcanic gases and hot spring waters from the Julong hot spring at Mt. Baekdu during the period from July 2015 to August 2016. Also, we confirmed the errors that $HCO_3{^-}$ concentrations of hot spring waters in the previous study (Lee et al. 2014) and tried to improve the problem. Dissolved $CO_2$ in hot spring waters was analyzed using gas chromatograph in Lee et al. (2014). Improving this, from 2015, we used TOC-IC to analysis dissolved $CO_2$. Also, we analyzed the $Na_2CO_3$ standard solutions of different concentrations using GC, and confirmed the correlation between the analytical concentrations and the real concentrations. However, because the analytical results of Julong hot spring water were in discord with the estimated values based on this correlation, we can't estimate the $HCO_3{^-}$ concentrations of 2014 samples. During the period of study, $CO_2/CH_4$ in volcanic gases are gradually decreased, and this can be interpreted in two different ways. The first interpretation is that the conditions inside the volcanic edifice are changing into more reduction conditions, and carbon in volcanic gases become more favorable to distribute into $CH_4$ or CO than $CO_2$. The second interpretation is that the interaction between volcanic gases and water becomes greater than past, and the concentrations of $CO_2$ which have much higher solubility in water decreased, relatively. In general, the effect of scrubbing of volcanic gas is strengthened during the quiet periods of volcanic activity rather than active periods. Meanwhile, the analysis of hot spring waters was done on the anion of acidic gases species, the major cation, and some trace elements (As, Cd, Re).

• Clinical and Experimental Pediatrics
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• v.48 no.7
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• pp.701-705
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• 2005

Purpose : Parents' genetic information plays an important role in their children's genetic expression. Human chromosome has 23-paternal chromosomes and 23-maternal chromosomes. Parental chromosomal translocation can induce clinical problems in their children because of imbalance in genetic information. We intent to analyze the cytogenentic and clinical features about children with maternal balanced translocation between chromosome 15 and 18. Methods : We detected by one family's FISH study of chromosome 15. We have evaluated children born to clinically normal parents about peripheral bood analysis, endocrine, metabolic, radiologic study, electroencephalogram and social & intelligence scale. and We analysis their clinical manifestation by hospital records. Results : Patient's father and elder sister are normal clinically and genetically. Her mother's chromosome show balanced translocation, 46, XX, t(15;18)(p11.2;p11.3). One child has 46, XX, der(18) t(15;18)(p11.2;p11.3), mental retardation, growth retardation, speech & social developmental delay, recurrent infection and mild mitochondria dysfunction. Her young brother has 46, XY, der(15) t(15;18) (p11.2;p11.3), mental retardation, aggressive behavior, obesity and speech developmental delay. Conclusion : In this study we observed the children with developmental delay, dysmorphic facial features, mental retardation, growth retardation associated with growth hormone deficiency and aggressive behavior due to unbalanced translocation between chromosome 15 and 18.