• Journal of The Geomorphological Association of Korea
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• v.25 no.1
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• pp.19-30
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• 2018

This study tries to infer fault lines and produce a map for the lines based on a classification of fault-related landforms and fluvial landformsin the Gyeongju area of the Yangsan Fault Valley. Fault activities in the study area are thought to be older than the time of river formation or stronger than the erosion by river, while the northern and southern parts of the study area seem to have experienced fault activities after valley formation. It is also possible that weaker fault activities than the erosion by river seem to have been prevailed in the parts. In the study area, the Gyeongju alluvial fan is located within a wide erosional valley at the joint area of the Yangsan and Ulsan Faults. From the distribution of the landforms, it is inferred that several fault lines parallel to the Yangsan Fault are distributed at both sides of the fault valley. In particular, the area from Bae-dong to Nogok-ri, Naenam-myeon shows the most obvious linearity of the landforms within the study area. Several fault lines with a direction of NNE-SSW are also found around the epicenter of the 2016 Gyeongju Earthquake.

• Proceedings of the KSR Conference
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• 2000.05a
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• pp.188-194
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• 2000

This study is about fault detection and fault area detection of LV circuit in Cab Cubicle system which have control of train to keep safety in High Speed Train. LV circuit is operated with diagnosis system like safety system. In this paper, we suggest a design and an implementation method to detect fault or to detect fault area automatically about LV circuit. The implemented system is tested successfully after implementation of some function. We expect reduction to diagnosis area or repair time by fault area module

• The Transactions of The Korean Institute of Electrical Engineers
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• v.57 no.2
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• pp.155-163
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• 2008

This paper presents a novel framework for analysis of power system wide-area blackout based on so called fault cascading scenarios. For a given power system operating state, "triggering" faults or a "seed faults" are chosen based on the probabilities estimated from the hazard rates. The fault probabilities reflect both the load and the weather conditions. Effects of hidden failures in protection systems are also reflected in establishing the fault propagation scenarios since they are one of the major causes for the wide-area blackouts. A tree type data structure called a PS-BEST(Power System Blackout Event Scenario Tree) is proposed for construction of the fault cascading scenarios, in which nodes represent various power system operating states and the arcs are the events causing transitions between the states. Arcs can be either probabilistic or deterministic. For a given initial fault, the total probability of leading to wide-area blackout is estimated by aggregating the individual probability of each fault sequence route leading to wide-area blackout. A case study is performed on the IEEE RTS-79(24 bus) system based on the fault data presented by the North American Electrical Reliability Council(NERC). Test results demonstrate the potentials and the effectiveness of the proposed technique for the future wide-area blackout analysis.

• Journal of Electrical Engineering and Technology
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• v.12 no.6
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• pp.2118-2126
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• 2017

The large-scale power system blackouts have indicated that conventional protection relays that based on local signals cannot fit for modern power grids with complicated setting or heavily loaded-flow transfer. In order to accurately detect various faulted lines and improve the fault-tolerance of wide-area protection, a novel multi-section weighed fault matching and detecting algorithm is proposed. The real protection vector (RPV) and expected section protection vectors (ESPVs) for five fault sections are constructed respectively. The function of multi-section weighed fault matching is established to calculate the section fault matching degrees between RPV and five ESPVs. Then the fault degree of protected line based on five section fault degrees can be obtained. Two fault detecting criterions are given to support the higher accuracy rate of detecting fault. With the enumerating method, the simulation tests illustrate the correctness and fault-tolerance of proposed algorithm. It can reach the target of 100% accuracy rate under 5 bits error of wide-area protections. The influence factors of fault-tolerance are analyzed, which include the choosing of wide-area protections, as well as the topological structures of power grid and fault threshold.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2001.04a
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• pp.66-73
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• 2001

Yangsan fault in the southeastern part of Korean peninsula has been locally reactivated along a prexisted fault during the late Pleistocene time. Geomorphological evidence of the reactivation is revealed at the northern segment(Yugye-ri, Tosung-ri areas) of the Yangsan fault. The reactivation is distinctively characterized by fault gouge and fracture zone with high frequency in the Yugye-ri area. Obique slip separation of the area is about three meters of the middle terrace. The cumulative vertical displacement is recognized after the formation of the middle terrace. Age of the reactivated faulting is constrained to during the formation of dissected valley deposits. Average vertical slip based on paleo-event is inferred to about 0.5-0.7 meter in this area.

• Economic and Environmental Geology
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• v.20 no.4
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• pp.247-260
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• 1987

As a part of study on the structure of the Yangsan Fault, geological and VLF EM studies have been made in the fault area approximately between Kyeongju and Eonyang. The result provides comparatively clear information on the trace of the fault and extent of fracture zone as well as the structural characteristics of the Yangsan Fault area. The location of fault trace identified from this VLF EM study coincides well in general with that expected from geological information of the area. And the extent of fault fracture zone turn out to be characterized by U shaped low resistivity zone whose width increases from north to south.

• Economic and Environmental Geology
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• v.26 no.2
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• pp.227-237
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• 1993

Lineaments in the Kyungsang basin most intensely develop in the East coast domain including the Yangsan fault, which dominantly run in NNE direction. The geometry of small fault population near or along the Yangsan fault represents the dominant strikes of N35E, high angle dips and shallowly plunging rakes with dextral movement sense. Stereographic solution on the Yangsan fault geometry gives the dip of 88SE, the slip direction of 17,024 and the slip rake of 18, which were determined from the strike (N23E) of the fault measured on map, and the average attitude (N35E, 84SE) and fault striation (16, 037) of small fault population considered as Riedel shears. It is judged from the geometry of small fault population to the main Yangsan fault and dragging features of bedding attitude near the fault that the Yangsan fault was produced from dextrally strike-slip movement. The movement of the Yangsan and the adjacent parallel faults is thought to be taken place much later than the other fault sets in the Kyungsang basin. It might occur during the geologic age from Eocence to early Miocene according to the consideration of K-Ar ages of the igneous rocks near the fault. The estimated paleostress state indicates ENE shortening and NNW extension. The displacement of the Yangsan fault in the study area is not constant along the fault but decreases from the south to the north. Taking the northern end of the study area as a separating point the whole extension of the Yangsan fault may be divided into southern and northern segments.

• The Journal of Engineering Geology
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• v.27 no.3
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• pp.207-215
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• 2017

The northern extension of the Dongrae Fault is inferred to transect the Ulsan Fault in the Gueo-ri area, Oedong-eup, ~15 km SE of Gyeongju City, Gyeongbuk province, S Korea. We conducted geological and geophysical (magnetic, electrical resistivity, and frequency domain electromagnetic) surveys to identify the extent and orientation of the Dongrae Fault in this region. Through joint interpretation of the geological and geophysical data sets, we confirm the presence of the Dongrae Fault and determine its strike ($N14^{\circ}E$). The Dongrae Fault is thought to cross the Ulsan Fault near Ipsil Bridge in the Gwangeo-ri area. Geophysical surveying revealed a fault damage zone that widens to the south, with a typical width of >200 m. Geological field surveys did not delineate the geometry of the Dongrae Fault because alluvial deposits overlie the fault in this area.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1998.10a
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• pp.235-240
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• 1998

Quaternary fault movement of the Ulsan fault system was interpreted by aenal photograph, field survey and trench excavation. The geomorphological evidences associated with active fault are clearly shown at Cheonbuk-myeon area, northern part of Ulsan fault system. In the trench wall one reverse fault(N 50$^{\circ}$E, 70$^{\circ}$E) is identified between basement rock (Miocene mudstone) and gravel deposits Another thrust fault (NS) extends up to the red and light brown soil layers. Middle terrace surface shows cumulative vertical displacements of about 3 to 7 m. The horizontai displacement of the red soil by faulting event is about 1.8 to 2.4m. The age of the fault activity is younger than that of the soil layer, which is roughly estimated to be late Quaternary (about 100Ka)

• Journal of The Geomorphological Association of Korea
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• v.28 no.3
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• pp.63-83
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• 2021

In the southeastern part of the Korean Peninsula, the Yangsan Fault, an active fault zone, has developed. Many earthquakes occur around these faults, and the possibility of earthquakes occurring along the branch faults is being discussed. On the other hand, the Yeongdeok Fault is reported in Yeongdeok-gun, which is the northern part of the Yangsan fault. In this study, goemorphic characteristics of a set faults found on the outcrop of the gentle slope of the coast of Byeonggok-myeon were analyzed and granulometric and geochemical characteristics of sediments and other materials, including fault gouges were analyzed. The outcrop of Byeonggok-myeon is the part of the fault core and can be divided into two parts. Theses fault are formed on the upper part of the Mesozoic bedrock and the tertiary sedimentary layer of red sand-supported clasts are covered in several sedimentary units. The faults were normal fault sets, and a number of vertical cracks were developed, and glossy surfaces were observed in the fault area. It appears that these faults have occurred after alluvial deposition had been formed. In the case of samples from fault gouges, there were differences in particle size and geochemical characteristics from the surrounding area.