• Economic and Environmental Geology
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• v.21 no.4
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• pp.335-348
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• 1988

The author aimed to describe the volcano-stratigraphy and petrology of the volcanic mass in the Koheung peninsula, South Cheolla province. The volcanic mass is composed of the volcanics and intrusives of late Cretaceous which extruded the Pre-cambrian metamorphic(Jirisan gneiss complex) and the early Cretaceous sedimentary(Duwon Formation) basement. The volcanic pile consists of, in ascending order, Bibongsan andesite, Koheung tuff and breccia, and Palyeongsan welded tuff, and are intruded by ring intrusives( intrusive breccia, andesite porphyry, intrusive rhyolite and fine-grained quartz-diorite) and central pluton(diorite, quartz monzodiorite, biotite granite and micrographic granite). Bibongsan andesite mainly consists of andesite tuff and lava. Koheung tuff consists of alternation of fine tuff, coarse tuff and lapilli tuff, and Palyeongsan welded tuff which overlies Koheung tuff, comprises K-feldspar and quartz phenocrysts, elongated brown fiamme, lithic fragments in matrix of devitrified brown glass shards, and mainly consists of rhyodacite to rhyolite vitric ash-flow tuff. The results of petrochemical studies of the igneous rocks suggest that the rocks were a serial differentiational products of fractional crystallization of calc-alkaline magma series. This study reveals that the volcanic mass in this area is inferred to the remnant of the resurgent cauldron, measuring 30 by 25 km in diameter. The cauldron block was lowered at least 1,000 m by ring fault displacement.

• Proceedings of the KIEE Conference
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• 1999.11c
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• pp.585-587
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• 1999

The rotorbody and rotor winding of generator are isolated by an insulator and the output characteristic of the generator is maintained in the best states. Only when an insulation resistance between them is over a certain extent. The aim of this research is to develop the simulator for rotor earth fault detection circuits. It is composed of the power resource which is to control the virtual field voltage, stepping motor which is to give virtual ground. It is possible to inspect with the device and program developed in this study in the same as real operating condition and evaluate the integrity of generator rotor through the function of data acquisition and graphic output. If these technologies will be applied to the inspection, prevent a damage of the generator and contribute to improve maintenance reliance.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.22 no.2
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• pp.155-161
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• 2008

The grounding systems provide a low resistance path for fault or normal currents into the earth. The material for reducing ground resistance is buried around the grounding electrode to increase its effective size of the electrode and thus to obtain low ground resistance. Increasing the contacting area with the grounding electrode is effective for lowering the ground resistance in soils. Using this idea the conductive expansion ground resistance reducing material was developed. In this paper experimental data has shown that the ground resistance reduction method using proposed material is superior to using a typically available commercial ground resistance reducing material.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.139-144
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• 2005

Multichannel seismic survey has conducied along the South Scotia Ridge which is located in the northern part of Weddell sea, Antarctic sea, The South Scotia Ridge is part of continental crust extended from Antarctic Peninsula. It borders on Oceanic plates, the Scotia sea plate and Powell basin. Transtensional tectonics along the sinistral transform fault plate boundary led to the creation of the present tectonic geomorphology of the South Scotia Ridge. The fan-shaped deposits with angular unconformities in the central depression is interpreted as a divergent tectonic movement along the ridge.

• Proceedings of the Korean Geotechical Society Conference
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• 2008.03a
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• pp.1400-1405
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• 2008

Execute surface of the earth geological survey for stability analysis of stealing cutting sides and investigated wide area nature of soil structure. Inflected DIPS that measure discontinuity's direction that develop to slope and is slope stability a wide use program for Stereographic Projection Method analysis that utilize geometrical correlation of stealing four sides and discontinuity surface. It is principle that angle of internal friction that is basis element of stability estimation applies direct shear test result on joint side, Examination is impossible by case execution, suppose by 30 angles that apply more conservatively in base rock slope sides usually and achieved analysis. When analyze, consider discontinuity's various adult that develop in research slope, after conduct first each discontinuity different assay falling into fault, joint, executed stability estimation which synthesize whole discontinuity data. When ailment element is recognized as analysis result, wished to present stability countermeasure way of most suitable to take into account of execution, stability, economic performance.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.170-175
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• 2003

Ground and rock mass considered in tunnelling have characteristics such as uncertainty, heterogeneity and structural complexity because they have been formed undergoing various geological events for a long period. So, it is difficult for engineers to predict behaviors of rock mass in tunneling. In the paper the authors describe the development of an integrated expert system prototype for site investigation, design and construction in tunnelling and introduce the case applying this system to the tunnel construction site under construction. Geostructure Research Group in Korea Institute of Construction Technology (KICT) has developed the system during the past 4 years. The system mainly consists of several modules which is related to the design, construction and management of tunnelling. The test site, Neung-dong tunnel is located in Ulsan, Korea. The geology map shows it may confront big fault zone whose width is over kilometres. With the networking system of ITIS, various information of face mapping, monitoring and other construction task can be transmitted into the database and GIS Server at real time. And necessary analyses can be carried out with the modules equipped in the system.

• Geophysics and Geophysical Exploration
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• v.7 no.2
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• pp.105-108
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• 2004

Immersive virtual reality has been used in areas of oil and gas exploration for visualization and analysis of various spatial data, such as wireline logs, 3-dimensional seismic data volume, formational boundaries, fault, and some other reservoir characteristics. Although virtual reality is a valuable tool in this area, in most cases, it requires a large budget. This paper describes the construction of a single screen, passive stereo, virtual reality, display system based on commodity, or otherwise, low-cost components. The core elements of the system are a PC with a two-channel 3-D graphics, two projects, and a polarized stereo. There are many options available for the major elements of such a system, and the basic system can be modified or adapted to many different styles of use.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.06a
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• pp.185-190
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• 2007

In this study, we developed the 2.5D EM modeling and inversion algorithm for cross-hole source and receiver geometry. Considering the cross-hole environment, we use a VMD (vertical magnetic dipole) as a source and vertical magnetic fields as a measuring data. Developed inversion algorithm is tested for the isolated block model which has a conductive and a resistivity anomaly respectively. For the conductive anomaly, its size and resistivity are inverted well on the inversion results, while for the resistive anomaly, the location of anomalous block is shown on the inverted section, but its values are far from the exact value. Furthermore, artificial conductive anomalies are shown around the resistive anomalous zone. If we consider the inversion artifact shown in the test inversion of restive block, it is almost impossible to image the resistive zone. However, the main target of EM tomography in the engineering problem is conductive target such as fault zone, and contaminated zone etc., EM tomography algorithm can be used for detecting the anomalous zone.

• 한국지구물리탐사학회:학술대회논문집
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• 2007.12a
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• pp.73-83
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• 2007

We interpreted marine seismic profiles in conjunction with swath bathymetric and magnetic data to investigate rifting to breakup processes at the eastern Korean margin that led to the separation of the southwestern Japan Arc. Analysis of rift fault patterns suggests that rifting at the Korean margin was primarily controlled by normal faulting resulting from extension rather than strike-slip deformation. Two extension directions of E-W and NW-SE for rifting are recognized. We interpret that the E-W direction represents initial rifting at the inner margin and the NW-SE direction probably represents the extension in response to tensional tectonics associated with the subduction of the Pacific Plate in the NW direction. No significant volcanism was involved in rifting. In contrast, the inception of sea floor spreading documents a pronounced volcanic phase which appears to reflect asthenospheric upwelling as well as rift-induced convection particularly in the narrow southern margin. We suggest that structural and igneous evolution of the Korean margin, although it is in a back-arc setting, can be explained by the processes occurring at the passive continental margin with magmatism influenced by asthenospheric upwelling.

• Journal of the Korean Geophysical Society
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• v.6 no.1
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• pp.31-38
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• 2003

Multi-channel seismic survey, which has been mainly employed in oil prospecting, is carried out as a high resolution shallow marine seismic exploration. Fault drop as small as 1 m can be resolved by employing high-resolution seismic survey. Similar to the effect of shallow inhomogenities in the land seismic data, due to occurrence of swell quite often higher than 1 m, shallow marine seismic data tend to be severely degraded. Suppression of such a swell effect is critical in processing of steps of marine seismic shallow high-resolution data. Compared to the moving average depth method, a newly developed method using cross-correlation technique is found out to be very effective in increasing the resolution of the shallow reflection events by accuratly elucidating the depth of sea bottom.