• Journal of the Korean earth science society
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• v.40 no.1
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• pp.56-67
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• 2019

In this study, we analyzed the intensity attenuation for M 6.0, 6.5, and 7.0 earthquakes using the broadband strong ground motion simulation platform based on the physical seismic modeling developed by the US Southern California Earthquake Center (SCEC). The location of the earthquake was assumed to be near the epicenter of the 2016 M 5.8 Gyeongju earthquake, but two of the representative US regional models provided by the SCEC strong ground motion simulation platform were used for the propagation model. One is the Central and Eastern United States (CEUS) model representing the intraplate region, and the other is the LA Basin model representing the interplate region. Five modeling methodologies are presented in the version 16.5 of the simulation platform, and Song and Exsim models were used in this study. In the analysis, we found that different intensity attenuation patterns can be observed with the same magnitude of earthquakes, especially depending on the region (CEUS vs LA Basin). Given the same magnitude and distance, the instrumental intensity in the CEUS region (intraplate) could be larger by a unit of 2 than that in the LA Basin region (interplate). Given the difference of intensity attenuation patterns observed in the study, it is important to know the regional intensity attenuation characteristics to understand the accurate level of seismic hazard imposed in the Korean Peninsula. This study also shows the level of the uncertainty of intensity attenuation if region specific attenuation characteristics are not considered.

• Computational Structural Engineering
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• v.17 no.2
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• pp.31-41
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• 2004

몇 일 전 필자는 대전에 위치한 한 연구소에 근무하고 계신 분으로부터 지진취약도 분석에 관한 문의 전화를 받았다. 그분의 대학 후배가 지진취약도에 대한 연구를 하고 싶다는 내용이었다. 최근 필자는 그분 외에도 다른 분들과 함께 지진취약도 분석 및 이를 확장한 바람에 의한, 혹은 홍수에 의한 구조물의 확률적 안전성 분석에 관한 논의를 하곤 하였다. 현재까지 국내에서는 구조물의 취약도 분석에 대한 연구가 그다지 활발하지 않으나, 이에 대한 관심은 지속적으로 증가할 것으로 보여진다. 지진취약도를 한마디로 요약하면, "임의의 크기를 갖는 지진이 발생하였을 때, 구조물에 어느 규모 이상의 손상이 발생할 확률"을 의미하는 것으로, 구조물의 확률적 지진안전성으로 부를 수 있다. 예를 들어, "최대지반가속도가 0.1g인 지진이 발생하였을 때, 해당 구조물에 보수를 요하는 수준 이상의 손상이 발생할 확률이 30%이다"와 같은 정보를 지진취약도 곡선으로부터 읽을 수 있다. (중략)

• Journal of the Earthquake Engineering Society of Korea
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• v.4 no.3
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• pp.45-53
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• 2000

강재 교각을 갖는 고가교량은 상부구조가 매우 큰 질량을 갖는 거대구조가 되고 규모가 큰 지진운동 하에서 대단히 큰 관성력을 받게 된다. 따라서 탄소성 동적응답 해석에 의해서 강재 교각의 지진거동을 파악하는 것이 필요하다 . 본 연구에서는, 탄소성 동적응답해석을 위한 합리적인 수치해석방법을 제시하고 이를 바탕으로 강재 교각에 대한 내진성 평가를 수행한다. 1995년 고베 지진 시 손상을 받은 강재 교각과 그 이후 재구축된 교각을 모델로 해서 국부좌굴 이전 소성화의 영향만을 고려한 강재 교각의 지진 거동을 파악한다. 입력지진파는 고베 지진시 관측된 Takatori 지진파이고 이를 가속도 진폭 조정하여 사용한다.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.04a
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• pp.62-66
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• 1997

확률론적 방법을 적용하여 국내의 4개 원전 부지의 설계지진을 분석하였다. 본 연구에서 사용된 방법은, 지금까지 원전 부지의 안전성 분야에서 적용되어 왔던 기존의 확률론적 재해도분석과는 다른 새로운 방법으로서, 기준확률의 분석과 제어지진의 결정을 위한 지진재해도 분해의 두 과정으로 구성된다. 분석에 사용된 지진원과 지진활동 특성값은 기존의 확률론적 지진재해도 분석에 사용되었던 입력자료이다. 이로부터 계산된 기준확률은 스펙트럼 가속도 감쇄식에 크게 좌우되는 것으로 나타났다. 기준확률1.0$\times$10-5에 대하여, 4개 원전 부지의 제어지진은 평균거리가 13~26kg, 평균 규모가 5.7~6.1 사이에 분포하는 것으로 나타났다. 이 값은 단지 현재의 입력자료에 근거하였을 때의 결과로서, 값 자체의 수치적인 의미보다는 전체적인 분석 과정을 검토하고 또한 현재의 입력자료와 새로운 방법이 조합되었을 때 산출되는 결과의 대략적인 수준을 파악하는데 더 큰 의미가 있다.

• Proceedings of the Korea Water Resources Association Conference
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• 2012.05a
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• pp.95-98
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• 2012

2011년 동일본 지진해일의 영향으로 우리나라에도 지진해일에 관한 관심이 높아지고 있다. 이러한 지진해일은 대규모 자연재해로써 한 번 발생하면 수많은 인명피해와 막대한 재산피해를 발생시킨다. 또한, 근래에 들어 세계적으로 해저지진의 발생빈도가 증가하는 추세이므로 이에 대한 대비책을 마련해둘 필요성이 있다. 하지만 이런 지진해일은 발생시점에 대한 예측이 불가능하기 때문에 역사 및 가상 지진해일의 수치모형실험결과를 이용하여 영향을 검토한다. 본 연구에서는 부산항 신항이 완공되면 추후 발전가능성이 높은 송도와 연도지역에 대해서 지진해일에 의한 최대 처오름높이와 최저 처내림높이를 계산하였으며, 모두 3가지 지진해일에 대해 수치모의 하였다.

• Journal of the Earthquake Engineering Society of Korea
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• v.10 no.6 s.52
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• pp.47-56
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• 2006

A method is presented for evaluating the economic efficiency of a semi-active magneto-rheological (MR) damper system for cable-stayed bridges under earthquake loadings. An optimal MR damper capacity maximizing the cost-effectiveness is estimated for various seismic characteristics of ground motion. The economic efficiency of MR damper system is addressed by introducing the life-cycle cost concept. To evaluate the expected damage cost, the probability of failure is estimated. The cost-effectiveness index is defined as the ratio of the sums of the expected damage costs and each device cost between a bridge structure with the MR damper system and a bridge structure with elastic bearings. In the evaluation of cost-effectiveness, the scale of damage cost is adopted as parametric variables. The results of the evaluation show that the MR damper system can be a cost-effective design alternative. The optical capacity of MR damper is increased as the seismic hazard becomes severe.

• The Journal of the Institute of Internet, Broadcasting and Communication
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• v.18 no.5
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• pp.203-208
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• 2018

In this paper, we selected power and power distribution facilities corresponding to urban infrastructure from the types of damage that could be caused by earthquakes and studied how they were calculated to damage. To calculate the damage, a graph of the magnitude of the damage was produced by applying the vulnerability curve calculation formula, which can be calculated for each type and type of facility. The scale of the earthquake and the probability of the occurrence of damage by the maximum earthquake acceleration were shown in the form of a vulnerability rate when the earthquake occurred in the urban infrastructure facility for utilizing the calculation result. It also applied a method of quantifying the fragility, which is a method of converting the calculated fragility into an integrated form, to represent a constant value for the magnitude of the damage. Continuing research, such as the method applied in this paper, could help identify in advance the types of structures affected by an earthquake and respond to reducing damage.

• Journal of the Korean Society of Surveying, Geodesy, Photogrammetry and Cartography
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• v.29 no.3
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• pp.311-318
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• 2011

On March 11, 2011, an 9.0-magnitude earthquake occurred near the northeastem coast Japanese. It was the largest earthquake that hit Japan since the beginning of modern seismometry. The earthquake occurred 179km east of the Sendai, Miyagi Prefecture, leaving about 27,000 of people confirmed dead, injured or missing due to the earthquake and tsunami. In this study, crustal Deformation in Mizusawa, Tsukuba and Usuda station were calculated based on GPS data in IGS station of Japan. The observation data were processed by precise point positioning and relative-positioning method using on-line GPS data processing services and a high precision scientific GPS/GLONASS data processing software. The coseismic displacements in IGS stations before and after the earthquake were analyzed using kinematic precise point positioning method, and the crustal deformation of the areas before and after the earthquake were precisely calculated using the relative-positioning method. The results of the study calculated precise coordination that the RMSE is maximum ${\pm}0.003m$, respectively and showed that Mizusawa station moved 2.6m southeast by the earthquake.

• The Journal of Engineering Geology
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• v.31 no.1
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• pp.43-53
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• 2021

Three-dimensional finite element analysis of 1,300 ton stainless water reservoirs was undertaken to consider differential settlement effects of the reservoir when subjected to earthquake loads. The earthquake load for large (>1,000 ton) water reservoirs are further determined using a specification established from the Korean Standards Association. The structural behavior of water reservoirs with differential settlements can be heavily dependent on seismic loading effects. Stress and displacement distributions are induced for various load combinations, including for with and without differential settlements. From numerical examples, the induced maximum displacements of the water reservoirs largely increase with differential settlements compared to those without differential settlements.

• Journal of the Korean Society of Hazard Mitigation
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• v.8 no.6
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• pp.73-79
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• 2008

Economic growth, industrialization and urbanization have made society more vulnerable than ever to seismic hazard in Korea. Although Korea has not experienced severe damage due to earthquakes during the last few decades, there is little doubt of the potential for large earthquakes in Korea as documented in the historical literature. As we see no immediate promise of short-term earthquake prediction with current science and technology, earthquake early warning systems attract more and more attention as a practical measure to mitigate damage from earthquakes. Earthquake early warning systems provide a few seconds to tens of seconds of warning time before the onset of strong ground shaking. To achieve rapid earthquake location, we propose to take full advantage of information from existing seismic networks; by using P wave arrival times at two nearest stations from the earthquake hypocenter and also information that P waves have not yet arrived at other stations. Ten earthquakes in the Korean peninsula and its vicinity are selected for the feasibility study. We observed that location results are not reliable when earthquakes occur outside of the seismic network. Earthquakes inside the seismic network, however, can be located very rapidly for the purpose of earthquake early warning. Seoul metropolitan area may secure $10{\sim}50$ seconds of warning time before any strong shaking starts for certain events. Carefully orchestrated actions during the given warning time should be able to reduce hazard and mitigate damages due to potentially disastrous earthquakes.