• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.3
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• pp.481-487
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• 2020

This study examined the behavior change of river levees during an earthquake by numerical analysis. Unlike conventional research using artificial earthquake waves, earthquake analysis was performed using real earthquake waves. The behavior of a river levee before and after an earthquake was compared and analyzed quantitatively. Studies show that the river levee has a safety factor of approximately 28.5% due to an earthquake. On the other hand, the minimum standard safety factor is satisfied. Vertical effective stress has decreased by 81.8% due to excess pore-water pressure generated by the earthquake. In addition, liquefaction occurs in most of the foundation soil. An examination of the stress-displacement behavior due to the earthquake revealed a large amount of settlement in the backfill layer. Most of the foundation soil yielded. Therefore, the target river levee is quite vulnerable to earthquakes. Through the results of this study, the necessity of refreshing the seismic design standards for river levees is required. This study can be used as basic data for estimating the approximate damage level and vulnerable areas.

• 한국지구물리탐사학회:학술대회논문집
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• 2005.05a
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• pp.3-7
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• 2005

Focal mechanism of the real and imaginary faults in the western coast of Japan has been assumed by examining the previous studies on the seismicity, seismic gap, fault behaviors, seismic zoning, and faults. In the area of no seismic information, the focal mechanism has been assumed to have the maximum influence on the tsunami height in the eastern coast of Korea. The tsunami height in a particular point of the eastern coast of Korea can vary up to 7 orders with the variation of the strike of the fault in a particular source point of the western coast of Japan with constant magnitude. Tsunami scenario DB including tile arrival times and tsunami heights has been constructing by using the assumed focal mechanism of the western coast of Japan. Tsunami warning system will be reinforced by using this tsunami scenario DB near future.

• Journal of the Korean Geophysical Society
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• v.8 no.2
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• pp.93-96
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• 2005

Focal mechanism of the real and imaginary faults in the western coast of Japan has been assumed by examining the previous studies on the seismicity, seismic gap, fault behaviors, seismic zoning, and faults. In the area of no seismic information, the focal mechanism has been assumed to have the maximum influence on the tsunami height in the eastern coast of Korea. The tsunami height in a particular point of the eastern coast of Korea can vary up to 7 orders with the variation of the strike of the fault in a particular source point of the western coast of Japan with constant magnitude. Tsunami scenario DB including the arrival times and tsunami heights has been constructing by using the assumed focal mechanism of the western coast of Japan. Tsunami warning system will be reinforced by using this tsunami scenario DB near future.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.5 s.39
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• pp.65-77
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• 2004

In this study, the base isolation systems for equipment in the NPP are presented and the responses of each isolation system are investigated. As for the base isolation systems, a natural rubber bearing (NRB) and a high damping rubber bearing (HDRB) are selected. As input motions, artificial time histories enveloping the US NRC RG 1.60 spectrum and the probability-based scenario earthquake spectra developed for the Korean nuclear power plant site as well as a typical near-fault earthquake record are used. Uniaxial, biaxial, and triaxial excitations are conducted with PGAs of 0.1, 0.2 and 0.25g. The reduction of the seismic forces transmitted to the equipment models are determined for different isolation systems and input motions.

• Journal of the Earthquake Engineering Society of Korea
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• v.9 no.6 s.46
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• pp.41-52
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• 2005

The seismic damage assessment due io the postulated earthquake was attempted for the buildings in the model district of Seoul City. The model district was selected to represent the typical structural and residential characteristics of Seoul City. The buildings in the model district were classified into 11 structural types. For each structural type, the capacity and fragility curves were constructed with parameters presented in HAZUS. The ground motions due to the postulated earthquakes were artificially generated and ground response analyses were done for three kinds of soil profiles classified with respect to the depth of surface soil layer. The probability of damage state of each structural type was calculated using capacity spectrum method and fragility curve. Finally, the calculated results were translated into GIS database and mapped to evaluate the seismic damage in the model district.

• The Journal of the Petrological Society of Korea
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• v.25 no.4
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• pp.325-334
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• 2016

Both 1900 years of historic literature and recent instrumental seismic records indicate the Korean Peninsula has repeatedly experienced small and large earthquakes. This study has used historical and instrumental records of Korea to investigate the characteristics of earthquakes in the peninsula. Results of GIS spatial analyses indicate Pyongyang, the capital of North Korea, is more vulnerable to the earthquake hazard than that of other regions in the Korean Peninsula. It is also noted that Pyongyang is exposed to high risks of other natural and social disasters because of the high population density and concentrated infra structures. Scenario shake map drawn up assuming a magnitude 6.7 earthquake, which was experienced in A.D. 502 in the area, indicates that 51.1% of the city are exposed to PGA 0.24 g or higher. Recent statistics by the Statistics Korea also indicates the North Korea is far more vulnerable to disasters than those in the South Korea. Results of the preliminary study provide essential information for comprehensive understanding of earthquake hazard estimation in Korea including the North Korea.

• Journal of the Earthquake Engineering Society of Korea
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• v.8 no.3
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• pp.43-52
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• 2004

This paper describes a method of evaluating seismic system performance of highway transportation network in California. The basic element that plays a crucial role in this study is the fragility information of highway bridges in Caltrans' (California Department of Transportation) freeway network. The bridge fragility information is expressed as a function of the ground motion intensity, such as peak ground acceleration (PGA) or peak ground velocity (PGV). Network damage was evaluated under the 1994 Northridge earthquake and scenario earthquakes. A probabilistic model was developed to determine the effect of repair of bridge damage on the improvement of the network performance as days passed after the event. As an example, the system performance degradation measured in terms of an index, “Drivers Delay”, is calculated for the Los Angeles area transportation system, and losses due to Drivers Delay with and without retrofit were estimated.

• The Journal of the Petrological Society of Korea
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• v.25 no.3
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• pp.253-260
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• 2016

A moment magnitude 3.1 earthquake occurred in the Seoul metropolitan region (SMR), Korea, on 9 February 2010. The unexpected shaking attracted much attention and raised concerns about the seismic hazards and risks in the SMR, which was regarded as an area safe from any earthquake hazard. The SMR has a population of 25 million and is one of the largest metropolitan areas in the world. A shakemap for a scenario earthquake with magnitude 6.5 and focal depth 12 km implies that the SMR will be exposed to serious risk because of its large population and the high vulnerability of its buildings. Although the instrumentally recorded earthquakes discussed in this article cannot be classified as major events, they should not be discounted as insignificant. Considering the low seismicity, micro-earthquakes below the magnitude of a conventional seismic network can achieve would be used to estimate background information in the evaluation of earthquake hazards and risks.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2018.05a
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• pp.254-257
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• 2018

In this paper, we implement the mobile application for disaster and safety accident response that can be easily accessed through smart phones to prevent the loss of life and poor awareness of safety to the increased number of disasters and accidents. A few of related mobile applications for accident response are served, and the most of them have the manual interfaces. In this paper, we implement the mobile application for scenario of the disaster such as earthquake and safety accident that can occur in daily life. It is organized in a form of a clear action option with user-friendly visual characters and can be used regardless of age group.

• Earthquakes and Structures
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• v.7 no.6
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• pp.1283-1301
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• 2014

Ground motion modification is extensively used in seismic design of civil infrastructure, especially where few or no recorded ground motions representative of the design scenario are available. A site in Los Angeles, California is used as a study site and 28 ground motions consistent with the design earthquake scenario are selected. The suite of 28 ground motions is scaled and modified in the time domain (TD) and frequency domain (FD) before being used as input to a bilinear SDOF system. The median structural responses to the suites of scaled, TD-modified, and FD-modified motions, along with ratios of he modified-to-scaled responses, are investigated for SDOF systems with different periods, strength ratios, and post-yield stiffness ratios. Overall, little difference (less than 20%) is observed in the peak structural accelerations, velocities, and displacements; displacement ductility; and absolute accelerations caused by the TD-modified and FD-modified motions when compared to the responses caused by the scaled motions. The energy absorbed by the system when the modified motions are used as input is more than 20% greater than when scaled motions are used as input. The observed trends in the structural response are predominantly the result of changes in the ground motion characteristics caused by modification.