• Journal of the Society of Disaster Information
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• v.17 no.4
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• pp.694-709
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• 2021

Purpose: In this study, earthquake-induced landslide risk assessment was conducted to provide basic data for efficient and preemptive damage prevention by selecting the erosion control work before the earthquake and the prediction and restoration priorities of the damaged area after the earthquake. Method: The study analyzed the previous studies abroad to examine the evaluation methodology and to derive the evaluation factors, and examine the utilization of the landslide hazard map currently used in Korea. In addition, the earthquake-induced landslide hazard map was also established on a pilot basis based on the fault zone and epicenter of Pohang using seismic attenuation. Result: The earthquake-induced landslide risk assessment study showed that China ranked 44%, Italy 16%, the U.S. 15%, Japan 10%, and Taiwan 8%. As for the evaluation method, the statistical model was the most common at 59%, and the physical model was found at 23%. The factors frequently used in the statistical model were altitude, distance from the fault, gradient, slope aspect, country rock, and topographic curvature. Since Korea's landslide hazard map reflects topography, geology, and forest floor conditions, it has been shown that it is reasonable to evaluate the risk of earthquake-induced landslides using it. As a result of evaluating the risk of landslides based on the fault zone and epicenter in the Pohang area, the risk grade was changed to reflect the impact of the earthquake. Conclusion: It is effective to use the landslide hazard map to evaluate the risk of earthquake-induced landslides at the regional scale. The risk map based on the fault zone is effective when used in the selection of a target site for preventive erosion control work to prevent damage from earthquake-induced landslides. In addition, the risk map based on the epicenter can be used for efficient follow-up management in order to prioritize damage prevention measures, such as to investigate the current status of landslide damage after an earthquake, or to restore the damaged area.

• Journal of the Korean Geographical Society
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• v.39 no.1
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• pp.56-69
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• 2004

We investigated the distribution and geomorphic development of alluvial fan in Gyeongju City including Cheonbuk area. According to a relative height to a river bed, alluvial fans of this area are divided into Higher surface, Middle surface, and Lower surface. As alluvial fans of Bulguk temple∼Ulsan bay area, the confluent fans in Cheonbuk and Gyeongju areas were formed by the Quaternary climatic change alternating glacial and interglacial stages, and the development of N-S and NW-SE fault lines. The Gyeongju alluvial fan, the largest in Korea, has been provided as the significant space for human activity since the prehistoric age. Bukcheon river formed the Gyeongju alluvial fan had not flowed over during the prehistoric and the ancient times. In contrast with general geomorphic characteristics, many springs in the Gyeongju alluvial fan are located in the middle part of the fan because ground water reaches to the surface. It is supposed that sedimental materials were not sufficiently piled up at lower reach of Bukcheon river due to the large deposits at upper and middle reach of the basin.

• Economic and Environmental Geology
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• v.38 no.3 s.172
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• pp.347-353
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• 2005

The geology of the Tumbang Lapan area consists of Permian to Carboniferous metamorphic rocks, Cretaceous granitic rocks, and Permian to Tertiary sedimentary and volcanic rocks. Three faults are developed in surveyed area, and are functioned as channels of the hydrothermal solution which farmed quartz veins within tuff3. In the mineralized area, argillic and propylitic alterations are dominant. Argillic altered rocks show the alteration mineral assemblages of kaolinte+sericite+quartz+chlorite+pyrite. Mineral association in propylitic alteration is chlorite+epidote+feldspar+quartz+pyrite+ magnetite. Vein type, fracture filling, stockwork are observed in survey area. As a result of analysis of samples from quartz veins and altered rocks, some mineralized rocks showed $0.01\~4.6g/t$ of gold.

• The Journal of the Petrological Society of Korea
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• v.5 no.2
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• pp.168-187
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• 1996

In the study area Uanggunbong-Samgunri area), Precambrian metamorphic complex, (Taebacksan gneiss complex, Hyundong gneiss complex, and Taebacksan schist complex) had undergone three different regional metamorphisms at least before Paleozoic. The Paleozoic sediments in the study area also had undergone three different metamorphisms at least. The first is low pressure type regional metamorphism, the second is low pressure type contact metamorphism due to the intrusion of Chunyang granite, and the last is medium pressure type metamorphism caused by thrust in south of Janggunbong area. The first metamorphism formed the prevailing metamorphic zones in the Paleozoic metasediments and the metamorphic grade of the first regional metamorphism increases from the chloritoid zone, through the staurolite zone, garnet zone, staurolite+biotite zone, and to the andalusite+biotite zone. The second metamorphism affected both Pre-Cambrian and Paleozoic metasediments located close to the Chunyang granite. The effect of the contact metamorphism is restricted to the very narrow zone around the granite. The third metamorphism that produced kyanite, is restricted to the very narrow region near the thrust fault in the south of Janggunbong with an E-W trend.

• The Journal of the Petrological Society of Korea
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• v.6 no.1
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• pp.45-51
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• 1997

Tectonic movements in the Mesozoic were significant events to structural evolution in East China, so far as to West Pacific area. Typical Mesozoic structures were formed and outcropped in Yanshanian mountain area in which Yanshanian movement was named. It is generally considered that the most of outcropping structures in this area were formed in Yanshanian movement. But general studies indicated recently that more than half of the folds were formed in Yanshanian movement. But general studies indicated recently that more than half of the folds were formed and most of fault were in great reverse activity during Indosinian movement in Late-Triassic epoch. The tectonic dynamics setting of Indosinian move ment is a N-S compressive stress system originated by northward movement of Sino-Korean massif and its collison with Xingan-Mongolia fold zone. A series of closed folds (nearly E-W axial trace)and some overturned folds were formed in Indosinian movement and incoaxially superposed by Yanshanian deformation, Faulting characteristcs in the area were thrust faulting caused by compressive stress in Indosinian movement, some of which appear to be positive structural inversion, and oblique-thrust caused by compressive-shear in Yanshanian movement.

• Economic and Environmental Geology
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• v.49 no.4
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• pp.315-323
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• 2016

This study reports a gneiss dome in the Hongseong area, southwestern margin of the Gyeonggi massif. This gneiss dome, named here as 'Oseosan dome' because it is located around the Oseosan, the highest peak along the western coastal area, is composed mainly of the Neoproterozoic to Paleozoic ortho- and paragneiss, mafic metavolcanic rock, and metadolerite. Migmatization affected these rock units, in which leucocratic(granitic) materials derived from anatexis frequently occur as patch and vein parallel to or cutting through internal foliation. The Oseosan dome shows overall concentric geometry and outward-dipping internal foliation, but also partly complicatedly changeable or inward-dipping foliation. Taking available petrological and geochronological data into account, the Oseosan dome is interpreted to be exhumed quickly into the upper crustal level during the Late Triassic, accompanied in part with anatexis and granite intrusion. In addition, extensional shear zone intruded by the Late Triassic synkinematic granite and sedimentary basin have been reported around the Oseosan dome. These evidences possibly suggest that the Oseosan dome formed in closely associated with the Late Triassic extensional movement and diapiric flow. Alternatively, 1) thrust- or reverse fault-related doming or 2) interference between independent folds during structural inversion of the Late Traissic to Middle Jurassic sedimentary basin can be also considered as dome-forming process. However, considering the northern limb of the Oseosan dome, cutting by the Late Traissic granite, and the southern limb, cutting by contractional fault reactivated after the Middle Jurassic, it is likely that the domal structure formed during or prior to the Late Triassic.

• The Journal of the Petrological Society of Korea
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• v.21 no.4
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• pp.397-403
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• 2012

Fe-REE deposits occurred in Jaeunri, Hongcheon formed by carbonatitic melts consist of 3 parts such as northern, middle and southern ore bodies showing discontinuous distribution, and extension shape of ore bodies can be figured through field survey and geometric analysis. Foliations in gneiss around northern and middle ore bodies represent NNE, whereas toward south its direction changes gradually from NE to ENE and finally N-S direction appears in southern ore body. From Jaeungyo to Saemaeulgyo geometric analysis from field work gives that fold shape in this area is open synclinal fold concavely and gently to NW with $45^{\circ}$ northwestward plunging axis, in contrast small scale anticline with $45^{\circ}$ northwestward plunging axis in Yagsooteo area near western part of Saemaeulgyo. Dragging effect could be occurred on these folds by WNW trending dextral strike-slip fault from Yagsooteo to Saemaeulgyo. New ore body can be confirmed from folding structure estimated by trend of foliation, and thus unidentified ore body may be exist under alluvial surface from middle to southern ore body and its distribution could show reversed "ㄱ", one of Korean consonants, considering with estimated strike and dip of foliations. This estimated extension of ore body figured out by structural analysis in the studied area works an important role for measuring of ore reserve and selecting of drilling site to find new ore body.

• The Journal of Engineering Geology
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• v.29 no.1
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• pp.1-12
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• 2019

Earthquake can change underground stress condition around the hypocenter and affect the fracture systems of the rocks. In Korea, the M5.8 Gyeongju earthquake on September 12, 2016 and M5.4 Pohang earthquake on November 15, 2017 occurred inside the Yangsan fault zone and possibly affected the fracture systems in the Yangsan fault zone and nearby rock masses. In this study, the characteristics of the fracture system (fracture orientation, number of the fractures, fracture spacing and aperture, dip angle, fracture density along depth, and relative rock strength) of the rocks in the low/intermediate level radioactive waste repository site located in the coastal area of the East Sea are analyzed by the impact of the Gyeongju and Pohang earthquakes using acoustic televiewer data taken from the boreholes at the radioactive waste repository site in 2005 and 2018. As a result of acoustic televiewer logging analysis, the fracture numbers, fracture aperture, and fracture density along depth overall increased in 2018 comparing to those in 2005. This increase tendency may be due to changes in the fracture system due to the impact of the earthquakes, or due to weathering of the wall of the boreholes for a long period longer than 10 years after the installation of the boreholes in 2005. In the borehole KB-14, on the whole, the orientation of the fractures and the average fracture spacing are slightly different between 2005 and 2018, while dip angle and relative rock strength in 2005 and 2018 are similar each other.

• The Journal of Engineering Geology
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• v.34 no.1
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• pp.1-12
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• 2024

South Korea's mining industry was actively developed until 1980, but subsequent declining profitability forced many mines to close. Most of the abandoned mines are susceptible to persistent subsidence because of the length of time since mining ceased. Accurate prediction of the locations and times of subsidence is difficult; therefore, this study aims to apply continuum analysis to past cases of subsidence to establish a method of predicting the location and magnitude of future subsidence. The study area is an area of ○○ mining located between the Yangsan fault zone and the Moryang fault zone, in which three subsidence events occurred between 2005 and 2009. Drilling surveys and electrical resistivity surveys were performed at subsidence sites determined the distribution of strata, and through laboratory tests obtained the physico-mechanical properties of the rock. Numerical analysis of the results found that the plastic status area includes the areas of actual subsidence and that continuum analysis can also be used to predict the location and magnitude of subsidence caused by mine goaf.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.10 no.1
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• pp.69-74
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• 2010

Now the CAN(controller Area Network) is using electronic modules as a serial communication which is very robust to noise. Especially the CAN is using for automotive part that very popular in which automotive electronic control module, engine controller unit, sensor modules, etc. but the CAN has the order of priority to linking node and also has fault confinement so using in these features that is applied to in factory automation product line. The CAN communication is basically very robust to electric noise so varied applying to others part. In this paper, we suggest to CAN interface for embedded system that is possible for error detection using two CAN nodes on Hi-speed, full-CAN.