• The Journal of Engineering Geology
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• v.8 no.2
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• pp.163-173
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• 1998

Suite of log analysis techniques consisting of geophysical well log, geological core log, and physical core log have been made to understand the well log responses and to determine the lithology of a test borehole-PABH1 located in Pungam sedimentary basin, Sosok, Hongchon-gun, Kangwon Province. Geological core logging has been precisely made over the cores taken between 64 and 124 meters, and 11 groups of rock types were deduced. Using the core samples divided by 11 groups, geophysical property measurements consisting of resistivity, natural gamma and density were made. Each rock group in the area is shown to have its characteristic physical response from geophysical well log and geophysical core logs. The outstanding physical responses particularly shown from siltstone, coarse sandstone to conglomerate, and granitic gneiss in the area were effectively used as keybeds in correlating the geophysical well logs to the result of geological core logs.

• Economic and Environmental Geology
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• v.29 no.5
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• pp.639-660
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• 1996

The lowest formation of the Cretaceous Gyeongsang Supergroup, the Nakdong Formation, unconformably overlies the gneiss complex basement in Hadong, Gyeongsangnam-do and Gwangyang, Chullanam-do. The Nakdong Formation of the study area is 500-600 m thick and occurs as a belt shape. Based upon lithology, sedimentary structure, and bedding geometry the formation consists of three conglomerate facies (Gd, Gn, Gic), five sandstone facies (Sh-n, Sh-i, Sp, Sr, Sm), and four mudstone facies (Mf, Mfn, Mc, Mv). Sandstone facies are the most prominent in the study area. The twelve facies can be grouped into five facies associations. The depositional settings are elucidated from analyses of 12 facies and five facies associations of the formation. The lower part of the Nakdong Formation was deposited in alluvial plain, and the middle and upper parts were in a riverine system. The lithologies of the Nakdong Formation of the Gyeongsang Basin have been considered to consist of generally conglomerates and pebbly sandstones that were accumulated in alluvial fans. But the common lithology of the study area is sandstone which was formed in lower part of alluvial fan or fluvial setting. It is supposed that the coarser sedimentary sequence distributed west to the study area should be eroded out after deposition and early uplift, and the finer sandstone sequence in the east remains behind. The mineral composition of sandstones and the clast composition of conglomerates indicate that the Nakdong Formation was derived mainly from the metamorphic source rocks. Some reworked intraclasts were also supplied from the intrabasinal sedimentary layers. Paleocurrent data collected from cross-beddings, ripple marks, asymmetric sand dune suggest that most sediments were transported from north to south during the Nakdong Formation time.

• Geophysics and Geophysical Exploration
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• v.1 no.3
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• pp.170-175
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• 1998

A systematic methodology is developed for the prediction of the lithology using electrofacies classification from wireline log data. Multivariate statistical techniques are adopted to segment well log measurements and group the segments into electrofacies types. To consider corresponding contribution of each log and reduce the computational dimension, multivariate logs are transformed into a single variable through principal components analysis. Resultant principal components logs are segmented using the statistical zonation method to enhance the quality and efficiency of the interpreted results. Hierarchical cluster analysis is then used to group the segments into electrofacies. Optimal number of groups is determined on the basis of the ratio of within-group variance to total variance and core data. This technique is applied to the wells in the Korea Continental Shelf. The results of field application demonstrate that the prediction of lithology based on the electrofacies classification works well with reliability to the core and cutting data. This methodology for electrofacies determination can be used to define reservoir characterization which is helpful to the reservoir management.

• 한국석유지질학회:학술대회논문집
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• spring
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• pp.10-14
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• 1998

A systematic methodology is developed for the electrofacies determination from wireline log data using multivariate statistical analysis. To consider corresponding contribution of each log and reduce the computational dimension, multivariate logs are transformed into a single variable through principal components analysis. Resultant principal components logs are segmented using the statistical zonation method to enhance the efficiency and quality of the interpreted results. Hierarchical cluster analysis is then used to group the segments into electrofacies. Optimal number of groups is determined on the basis of the ratio of within-group variance to total variance and core data. This technique is applied to the wells in the Korea Continental Shelf. The results of field application demonstrate that the prediction of lithology based on the electrofacies classification matches well to the core and the cutting data with high reliability This methodology for electrofacies classification can be used to define the reservoir characteristics which are helpful to the reservoir management.

• Economic and Environmental Geology
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• v.33 no.1
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• pp.51-59
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• 2000

As a part of natural hazard assessment, regional slope stability analysis was conducted using Geoscientific Information System (GIS) in the northern area of Chungju Lake. Selected factors which affect the slope stability in the study area were lithology, soil, density of lineament, groundwater level, dip of slope, aspect of slope, and geological engineering properties. Geological structural domains were determined by collected data of joint orientation from about 200 sites in order to produce a slope instability map. Potential type of failure and its direction could be expected through the domains. And a slope instability map was produced, comparing the representative orientations of the domains with the orientations of the slopes which were made through TIN module in ARC/INFO. Under the consideration of environmental geological characteristics of the study area, rating and weighting of each factor of slope stability analysis were decided and spatial analysis of regional slope stability was couducted through overlaying technique of GIS. The result of areal distribution of slope stability showed that the most unstable area was the area between Mt. Pudae and Mt. Jubong, and the northern area of the railway station, Samtan.

• Proceedings of the Korean Geotechical Society Conference
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• 2010.09a
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• pp.423-427
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• 2010

To develope SOC(social overhead capita) which constructs the railroad, highway etc., the geo-technical foundation have to be well understood for the safety works. In this paper, we selected Moonkyung area for the study area, which has various geological units and geological structure including the big thrust and fold. By this reason one of the geo-technical information is the engineering geology map. To make the map, lithology and soil distribution with drilling data are important elements. Three dimensional geo-infomation is established by fence diagram which is several geological cross sections and/or computer software 3D Geomodeller, EarthVision, GSI3D, Gocad.

• Proceedings of the KSRS Conference
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• 2004.10a
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• pp.310-313
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• 2004

The aim of this study is to evaluate the hazard of landslides at Penang, Malaysia, using a Geographic Information System (GIS) and remote sensing. Landslide locations were identified in the study area from interpretation of aerial photographs and from field surveys. Topographical and geological data and satellite images were collected, processed, and constructed into a spatial database using GIS and image processing. The factors chosen that influence landslide occurrence were: topographic slope, topographic aspect, topographic curvature and distance from drainage, all from the topographic database; lithology and distance from lineament, taken from the geologic database; land use from TM satellite images; and the vegetation index value from SPOT satellite images. Landslide hazardous area were analysed and mapped using the landslide-occurrence factors by logistic regression model. The results of the analysis were verified using the landslide location data and compared with probabilistic model. The validation results showed that the logistic regression model is better prediction accuracy than probabilistic model.

• Geophysics and Geophysical Exploration
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• v.16 no.4
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• pp.268-274
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• 2013

Continuous seismic observation of volcanic earthquakes related to migration of magma or gas, is one of the most important methods used to monitor active volcanoes. In this review paper, we introduce the characteristics of volcanic earthquakes and their classification based on locations of foci, waveforms, frequencies, lithology, and source mechanisms. We also present some examples of successful warnings of volcanic eruptions and the present status of some observations of volcanic earthquakes in Japan, the United States, Italy, and New Zealand.

• Proceedings of the Korean Geotechical Society Conference
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• 2000.11a
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• pp.629-634
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• 2000

Rockfall protection fence which is used for mitigation of rockfall hazard, has been constructed without consideration of lithology, height and dip angle of rock slope. However, those factors should be considered for the construction of the protection fence. In addition, the protection fence should be evaluated its performance by in-situ test in order to utilize the fence effectively. This is the first full sized rockfall test in Korea. For this test, the rock cut slope whose height is about 20 m and dip angle is 65 $^{\circ}$ has been chosen. Based on the preliminary simulation procedure, four different concrete balls (0.5 ton, 1.0 ton, 2.0 ton and 5.0 ton) were prepared and four different types of protection fence were constructed. The results of this test will be utilized in the establishment of rockfall protection fence construction manual.

• Proceedings of the Korean Geotechical Society Conference
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• 2005.03a
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• pp.765-776
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• 2005

As a result of industrial advancement and land development, a number of highway slopes have been gradually formed and numerous problems related to their stability have been frequently caused. Generally, major factors for rock slope stability are lithology, slope inclination, slope height, degree of weathering, precipitation, condition of groundwater and so onl. Many complex factors are mostly involved in the collapse of rock slopes. In this study, a database for 94 collapsed Jungang highway slopes were set up using GIS program through literature search, site investigation, geological map and Korea tectonic province map. The analyses for the collapsed factor including sort of rock(by origin), tectonic province, highway direction, slope gradient and direction, degree of weathering, slope height were carried.