• The Korean Journal of Petroleum Geology
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• v.5 no.1_2 s.6
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• pp.9-15
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• 1997

The study area is located in the Central Bransfield Basin, Antarctica. To analyze the morphology of seafloor, structure of basement, and seismic stratigraphy of the sedimentary layers, we have acquired, processed, and interpreted the multi-channel seismic data. The northwest-southeastern back-arc extension dramatically changes seafloor morphology, volcanic and fault distribution, and basin structure along the spreading ridges. The northern continental shelf shows a narrow, steep topography. In contrast, the continental shelf or slope in the south, which is connected to the Antarctic Peninsula, has a gentle gradient. Volcanic activities resulted in the formation of large volcanos and basement highs near the spreading center, and small-scale volcanic diapirs on the shelf. A very long, continuous normal fault characterizes the northern shelf, whereas several basinward synthetic faults probably detach into the master fault in the south. Four transfer faults, the northwest-southeastern deep-parallel structures, controlled the complex distributions of the volcanos, normal faults, depocenters, and possibly hydrocarbon provinces in the study area. They have also deformed the basement structure and depositional pattern. Even though the Bransfield Basin was believed to be formed in the Late Cenozoic (about 4 Ma), the hydrocarbon potential may be very high due to thick sediment accumulation, high organic contents, high heat flow resulted from the active tectonics, and adequate traps.

• Journal of the Korean Geophysical Society
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• v.1 no.1
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• pp.31-40
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• 1998

Gravimetric and magnetic surveys were conducted in order to reveal near-surface structures such as basements, faults, and fracture zones in an area near Angang, where the Yangsan fault is believed to pass through. Along two lines approximately perpendicular to the strike of the major fault, gravity and magnetic data were measured at 67 stations with a 15 m interval and at 296 stations with a 3 m interval, respectively. Average depth to the magnetic basement is estimated using the spectral analysis method to be 8.5 and 10.0 m along lines located to the east and the west of the Hyeongsan river, respectively. Average value of reduced gravity on the east line is higher than that on the west by the amount of 1.71 mGal, which indicates that the basement rocks are more severely fractured in the western part. Forward gravity modeling along the east line indicates that a fracture zone extends westward from a fault located 210 m west of the eastern end. Density and depth to the bottom of the fracture zone are estimated to be 2.44 g/cm3 and 70 m, respectively. The gravity model study also indicates presence of a small graben, 190 m wide and 3.5 m deep on an average, on the basement surface. The earth surface above the graben is approximately 44 cm lower than the nearby surface. This indicates that the graben might have been formed by recent fault movements.

• The Korean Journal of Petroleum Geology
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• v.2 no.2 s.3
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• pp.59-70
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• 1994

The Cenozoic geological structures and the tectonic evolution of the southern Ulleung Basin were studied with seismic profiles and exploration well data. Basement structure of the Korea Strait is distinctly characterized by normal faults trending northeast to southwest. The normal faults of the basement are most likely related to the initial liking and extensional tectonics of Ulleung Basin. Tsushima fault along the west coast of Tsushima islands runs northeastward to the central Ulleung Basin. The Middle Miocene and older sequences in the Tsushima Strait show folds and faults mostly trending northeast to southwest. These folds and faults may be interpreted as a result of compressional tectonics. The Late Miocene to Qauternary sequences are not much deformed, but numerous faults mostly N-S trending are dominated in the Tsushima Strait. The Ulleung Basin was in intial rifting during Oligocene, and then active extension and subsidence from Early to early Middle Miocene. Therefore SW Japan separated from Korea Peninsula and drifted toward southeast, and Ulleung Basin was formed as a pull-apart basin under dextral transtensional tectonic regime. During rifting and extensional stage, Tsushima fault as a main tectonic line separating SW Japan block from the Korean Peninsula acted as a normal faulting with right-lateral strike-slip motion as SW Japan drifted southeastward. During middle Middle Miocene to early Late Miocene, the opening of Ulleung basin stopped and uplifted due to compressional tectonics. The southwest Japan block converging on the Korean Peninsula caused compressional stress to the southern margin of Ulleung Basin, resulting in strong deformation under sinistral transpressional tectonic regime. Tsushima fault acted as thrust fault with left-lateral strike-slip motion. From middle Late Miocene to Quaternary, the southern margin of Ulleung Basin has been controlled by compressional motion. Thus the Tsushima fault still appears to be an active thrust fault by compressional tectonic regime.

• Journal of the Korean Society of Radiology
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• v.83 no.2
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• pp.439-443
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• 2022

Hibernoma is a rare benign tumor of brown adipose tissue. Herein, we report a case of axillary hibernoma in a 53-year-old female and discuss the various radiologic findings. The US revealed a 4.5-cm well-defined oval heterogenous hyperechoic mass in the right axilla with anterior displacement of the axillary vessels. Non-enhanced chest CT showed a 5.0-cm well defined, oval, and low-attenuated mass. MRI demonstrated a 5.5-cm mass with heterogeneous intermediate-to-high signal intensity on T1-and T2-weighted images and irregular enhancement at the peripheral portion. The patient underwent an US-guided core needle biopsy and the final diagnosis was hibernoma.

• Journal of the Korean Society of Radiology
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• v.18 no.3
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• pp.231-237
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• 2024

Brain injury causes persistent disability in survivors, and epidural hematoma(EDH) and subdural hematoma (SDH) resulting from cerebral hemorrhage can be considered one of the major clinical diseases. In this study, we attempted to automatically segment and hematomas due to cerebral hemorrhage in three dimensions based on computed tomography(CT) images. An improved GVF(gradient vector flow) algorithm was implemented for automatic segmentation of hematoma. After calculating and repeating the gradient vector from the image, automatic segmentation was performed and a 3D model was created using the segmentation coordinates. As a result of the experiment, accurate segmentation of the boundaries of the hematoma was successful. The results were found to be good even in border areas and thin hematoma areas, and the intensity, direction of spread, and area of the hematoma could be known in various directions through the 3D model. It is believed that the planar information and 3D model of the cerebral hemorrhage area developed in this study can be used as auxiliary diagnostic data for medical staff.

• Journal of Dental Rehabilitation and Applied Science
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• v.33 no.4
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• pp.278-283
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• 2017

Purpose: The aim of this study was to evaluate the interdental distances of anterior, premolar, and molar teeth at the cementoenamel junction (CEJ) and 2 mm below the CEJ in healthy natural dentition with cone-beam computerized tomography (cone-beam CT) in order to provide valuable data for ideal implant positioning relative to mesiodistal bone dimensions. Materials and Methods: Two hundred patients who visited Dental Hospital, Wonkwang University, who had natural dentition with healthy interdental papillae, and who underwent cone-beam CT were selected. The cone-beam CT images were converted to digital imaging and communication in medicine (DICOM) files and reconstructed in three-dimensional images. To standardize the cone-beam CT images, head reorientation was performed. All of the measurements were determined on the reconstructed panoramic images by three professionally trained dentists. Results: At the CEJ, the mean maxillary interdental distances were 1.84 mm (anterior teeth), 2.07 mm (premolar), and 2.08 mm (molar), and the mean mandibular interproximal distances were 1.55 mm (anterior teeth), 2.20 mm (premolar), and 2.36 mm (molar). At 2mm below the CEJ, the mean maxillary interdental distances were 2.19 mm (anterior teeth), 2.51 mm (premolar), and 2.60 mm (molar), and the mean mandibular interproximal distances were 1.86 mm (anterior teeth), 2.53 mm (premolar), and 3.01 mm (molar). Conclusion: The interdental distances in the natural dentition were larger at the posterior teeth than at the anterior teeth and also at 2 mm below the CEJ level compared with at the CEJ level. The distances between mandibular incisors were the narrowest and the distances between mandibular molars were the widest in the entire dentition.

• Economic and Environmental Geology
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• v.38 no.2 s.171
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• pp.143-153
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• 2005

Euiseong subbasin, included in the Kyungsang Basin, was created by the result of volcanic activity in the late Cretaceous, and contacts with Milyang and Youngyang subbasins by Palgongsan and Andong faults, respectively. In this study, geophysical survey is implemented fur investigating surface and subsurface geologic structure in Euiseong subbasin which composed with the complex of volcanic and plutonic rocks. To understand surface geologic feature, IRS satellite image and DEM(Digital Terrain Map) are used for analyzing lineament and its density. The numbers of lineaments show major trend in $N55^{\circ}\~65^{\circ}W$, and aspects of lineament lengths show major trend in $N55^{\circ}\~65^{\circ}W$ and N-S directions. 13 delineate subsurface density discontinuity; Power spectrum analysis was implemented for gravity anomaly data, resulting $4-5{\cal}km$ depth of basin basement and $0.5-0.6{\cal}km$ depth of shallow discontinuity. From the result of power spectrum analysis, 2.5-D modelings were implemented along two profiles of A-A' and B-B', and they show subsurface geology in detail. Analytic signal method for detecting boundaries of magnetic basements show 0.001-130 nT/m values, and high energy area show good correspondency with the boundaries of Palgongsan granite and caldera areas in Euiseong subbasin.

• Journal of the Korean Society of Radiology
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• v.79 no.6
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• pp.303-310
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• 2018

Purpose: To evaluate the CT features of incidental breast lesions on chest CT and to suggest useful criteria for referral to a specialized breast unit. Materials and Methods: Between May 2009 and April 2014, enhanced chest CT examination reports containing the key word 'breast' were reviewed retrospectively. Patients who had incidental breast lesion and were referred to a specialized breast unit and then underwent pathological confirmation or follow-up over a 1-year period were included. Finally, 86 patients (all female, mean age, $48.9{\pm}12.6years$) were enrolled. Two radiologists evaluated lesion characteristics, including size, shape, margins, and enhancement. The correlations between the CT features and pathologies were evaluated, and the diagnostic accuracy of CT features in various combinations was assessed. Results: Among the CT features, irregular shape, non-circumscribed margin, and high contrast enhancement were different between malignant and benign lesions (p < 0.05). The combination of non-circumscribed margin and high contrast enhancement had the highest accuracy (97.7%). Conclusion: Reliable CT features for incidental malignant breast masses are irregular shape, non-circumscribed margin, and high contrast enhancement. The combination of non-circumscribed margin and high contrast enhancement could help distinguish incidental malignant breast lesions and indicate referral to a specialized breast unit.

• Korean Journal of Mineralogy and Petrology
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• v.36 no.1
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• pp.55-72
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• 2023

This study aims to identify the fault zone architecture and geometric and kinematic characteristics of the Yeongdeok Fault, based on the geometry and kinematic data of various structural elements obtained by detailed field survey and anisotropy of magnetic susceptibility (AMS) of the fault rocks. The Yeongdeok Fault extends from Opo-ri, Ganggu-myeon, Yeongdeok-gun to Gilgok-ri, Maehwa-myeon and Bangyul-ri, Giseong-myeon, Uljin-gun, and cuts various rock types from the Paleo-proterozoic to the Mesozoic with a range of 4.6-5.0 km (4.77 km in average) of right-lateral offset or forms the rock boundaries. The fault is divided into four segments based on its geometric features and shows N-S to NNW strikes and dips of an angle of ≥ 54° to the east at most outcrops, even though the outcrops showing the westward dipping (a range of 54°-82°) of fault surface increase as it goes north. The Yeongdeok Fault shows the difference in the fault zone architecture and in the fault core width ranging from 0.3 to 15 m depending on the bedrock type, which is interpreted as due to differences in the physical properties of bedrock such as ductility, mineral composition, particle size, and anisotropy. Combining the results of paleostress reconstruction and AMS in this and previous studies, the Yeongdeok Fault experienced (1) sinistral strike-slip under NW-SE maximum horizontal principle stress (σ_Hmax) and NE-SW minimum horizontal principle stress (σ_Hmin) in the late Cretaceous to early Cenozoic, and then (2) dextral strike-slip under NE-SW maximum horizontal principle stress (σ_Hmax) and NW-SE minimum horizontal principle stress (σ_Hmin) in the Paleogene. It is interpreted that the deformation caused by the Paleogene dextral strike-slip movement was the most dominant, and the crustal deformation was insignificant thereafter.

• Journal of IKEEE
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• v.3 no.2 s.5
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• pp.178-185
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• 1999

Geological structures such as fault and fracture patterns provide important information about preliminary exploration of mineralized areas and geological characterization. They may be recognized and interpreted from satellite images as line-like features usually referred to as lineaments. A proposed filtering method taking the sums azimuth angle into account is utilized, by which linear edges from low contrast areas where features extend parallel to the sun direction and in mountain shadow can be effectively extracted. Then, generalized Hough transform is applied to extract lineaments which correspond to fault and fracture patterns.