• Title, Summary, Keyword: 지진원 스펙트럼

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Site responses of Japanese stations near the epicenter and Korean stations for the Fukuoka earthquake (후쿠오카 지진('05. 3. 20, $M_{JMA}=7.0$)에 대한 일본 인근 지진관측소와 국내 지진관측소의 주파수응답특성 비교)

  • Yun Kwan-Hee;Park Dong-Hee;Chang Chun-Jung;Choi Weon-Hack;Lee Dae-Soo
    • 한국지구물리탐사학회:학술대회논문집
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    • pp.79-86
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    • 2005
  • The apparent source spectrum of the Fukuoka earthquake is estimated at the seismic basement by removing from the observed spectra at Korean seismic stations the path and site responses that were previously revealed through inversion process applied to large spectral D/B accumulated until 2004. The approximate source spectrum is also estimated by using data recorded near the epicenter from various Japanese seismic networks and compared with the Korean source spectrum. The comparison result shows that there is good agreement among source spectra estimated based on the data from seismic networks of Korea at large distances (190km

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Site Responses of Japanese Stations Near the Epicenter and Korean Stations for the Fukuoka Earthquake (후쿠오카 지진 ('05. 3. 20, $M_{JMA}=7.0$)에 대한 일본 인근 지진관측소와 국내 지진관측소의 주파수응답특성 비교)

  • Yun, Kwan-Hee;Park, Dong-Hee;Chang, Chun-Jung;Choi, Weon-Hack;Lee, Dae-Soo
    • Journal of the Korean Geophysical Society
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    • v.8 no.1
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    • pp.15-21
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    • 2005
  • The apparent source spectrum of the Fukuoka earthquake is estimated at the seismic basement by removing from the observed spectra at Korean seismic stations the path and site responses that were previously revealed through inversion process applied to large spectral D/B accumulated until 2004. The approximate source spectrum is also estimated by using data recorded near the epicenter from various Japanese seismic networks and compared with the Korean source spectrum. The comparison result shows that there is good agreement among source spectra estimated based on the data from seismic networks of Korea at large distances (190 km

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Characteristics of the Point-source Spectral Model for Odaesan Earthquake (M=4.8, '07. 1. 20) (오대산지진(M=4.8, '07. 1. 20)의 점지진원 스펙트럼 모델 특성)

  • Yun, Kwan-Hee;Park, Dong-Hee
    • Geophysics and Geophysical Exploration
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    • v.10 no.4
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    • pp.241-251
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    • 2007
  • The observed spectra from Odaesan earthquake were fitted to a point-source spectral model to evaluate the source spectrum and spatial features of the modelling error. The source spectrum was calculated by removing from the observed spectra the path and site dependent responses (Yun, 2007) that were previously revealed through an inversion process applied to a large accumulated spectral dataset. The stress drop parameter of one-corner Brune's ${\omega}^2$ source model fitted to the estimated source spectrum was well predicted by the scaling relation between magnitude and stress drop developed by Yun et al. (2006). In particular, the estimated spectrum was quite comparable to the two-corner source model that was empirically developed for recent moderate earthquakes occurring around the Korean Peninsula, which indicates that Odaesan earthquake is one of typical moderate earthquakes representative of Korean Peninsula. Other features of the observed spectra from Odaesan earthquake were also evaluated based on the commonly treated random error between the observed data and the estimated point-source spectral model. Radiation pattern of the error according to azimuth angle was found to be similar to the theoretical estimate. It was also observed that the spatial distribution of the errors was correlated with the geological map and the $Q_0$ map which are indicatives of seismic boundaries.

The Acceleration Response Spectrum for Simulated Strong Motions Considering the Earthquake Characteristics of the Korean Peninsula (한반도 지진특성을 고려하여 모사된 강진동에 대한 가속도 응답스펙트럼)

  • Kim, Sung-Kyun
    • Journal of the Korean earth science society
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    • v.28 no.2
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    • pp.179-186
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    • 2007
  • The response spectrum is one of the important basic materials for the aseismic design. Numerous strong ground motions based on the seismic source characteristics for the earthquakes occurring in the Korean Peninsula were simulated to obtain the response spectra by using the computer program, SMSIM, developed by Boore (2005). Through the extensive review of other study outcomes, the input data for the simulation such as seismic source and attenuation characteristics were selected. The spectra obtained from the simulated ground motions were normalized to 1.0 g of zero period acceleration and compared with the standard response spectrum proposed by the U.S. Atomic Energy Commission (AEC, 1973). In this study, we found that the spectral values for the response spectra appeared to be larger than those of the standard spectrum in the frequency band above roughly 10 Hz. The variation of resulting response spectra was evaluated with the variable stress drops. It was shown that the spectral amplitude of the spectrum for the larger stress drop denotes higher value in the low frequency range.

Analysis of Characteristics of Seismic Source and Response Spectrum of Ground Motions from Recent Earthquake near the Backryoung Island (최근 백령도해역 발생지진의 지진원 및 응답스펙트럼 특성 분석)

  • Kim, Jun-Kyoung
    • Geophysics and Geophysical Exploration
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    • v.14 no.4
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    • pp.274-281
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    • 2011
  • We analysed ground motions form Mw 4.3 earthquake around Backryoung Island for the seismic source focal mechanism and horizontal response spectrum. Focal mechanism of the Backryoung Islands area was compared to existing principal stress orientation of the Korean Peninsula and horizontal response spectrum was also compared to those of the US NRC Regulatory Guide (1.60) and the Korean National Building Code. The ground motions of 3 stations, including vertical, radial, and tangential components for each station, were used for grid search method of moment tensor seismic source. The principal stress orientation from this study, ENE-WSW, is consistent fairly well with that of the Korean Peninsula. The horizontal response spectrum using 30 observed ground motions analysed and then were compared to both the seismic design response spectra (Reg Guide 1.60), applied to the domestic nuclear power plants, and the Korean Standard Design Response Spectrum for general structures and buildings (1997). Response spectrum of 30 horizontal ground motions were used for normalization with respect to the peak acceleration value of each ground motion. The results showed that the horizontal response spectrum revealed higher values for frequency bands above 3 Hz than Reg. Guide (1.60). The results were also compared to the Korean Standard Response Spectrum for the 3 different soil types and showed that the vertical response spectra revealed higher values for the frequency bands below 0.8 second than the Korean Standard Response Spectrum (SD soil condition). However, through the qualitative improvements and quantitative enhancement of the observed ground motions, the conservation of horizontal seismic design response spectrum should be considered more significantly for the higher frequency bands.

Development of Attenuation Equations of ground Motions in the Southern Part of the Korean Peninsula (한반도 남부 지역의 지진동 감쇄식 개발)

  • 노명현
    • Journal of the Earthquake Engineering Society of Korea
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    • v.3 no.1
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    • pp.21-28
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    • 1999
  • The objective of the study is to develop attenuation equations of the ground motions in the southern part of the Korean peninsula. The earthquake source characteristics and the medium properties were estimated from available instrumental earthquake records and used as input parameters. The peak ground accelerations(PGA) and pseudo-velocity response spectra(PSV) were simulated by the random vibration theory. The attenuation equations for the PGA and PSV were constructed in terms of local magnitudes and hypocentral distances.

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Discrimination between Earthquakes and Explosions Recorded by the KSRS Seismic Array in Wonju, Korea (원주 KSRS 지진 관측망에 기록된 지진과 폭발 식별 연구)

  • Jeong, Seong Ju;Che, Il-Young;Kang, Tae-Seob
    • Geophysics and Geophysical Exploration
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    • v.17 no.3
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    • pp.137-146
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    • 2014
  • This study presents a procedure for discrimination of artificial events from earthquakes occurred in and around the Korean Peninsula using data set in the Wonju KSRS seismograph network, Korea. Two training sets representing natural and artificial earthquakes were constructed with 150 and 56 events, respectively, with high signal to noise ratio. A frequency band, Pg(4-6 Hz)/Lg(5-7 Hz), which is optimal for the discrimination of seismic sources was derived from the two-dimensional grid of Pg/Lg spectral amplitude ratio. The corrections for the effects of earthquake magnitude and hypocentral distance were carried out for improvement of discrimination capability. For correcting the effect of magnitude dependence due to the inverse proportionality of corner frequency to seismic moment, the Brune's source spectrum was subtracted from the observation spectrum. The spectrum was corrected using the optimal damping coefficient to remove damping effect with the hypocentral distance. The effect of locally varying spectrum ratio was cancelled correcting variation of wave propagation along the ray path. The performance in discrimination between training sets of natural and artificial events was compared using the Mahalanobis distance in each step of correction. The procedure of magnitude, distance, and path corrections show clear improvements of the discrimination results with increasing Mahalanobis distance, from 1.98 to 3.01, between two training sets.

Source Parameters of the Southern Yellow Sea Earthquake Occurred on July 25, 1994 (1994년 7월 25일 발생한 황해남부 지진의 지진원 요수)

  • 김성균;김민선
    • Journal of the Earthquake Engineering Society of Korea
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    • v.2 no.1
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    • pp.113-118
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    • 1998
  • 1994년 7월 25일 발생한 황해남부 지진(Mb=5.5)의 지진원 요소들을 결정하였다. 지진원 요소들을 결정하기 위하여 이 지진에 대하여 이전의 연구에서 얻어진 지진발생기구를 사용하였다. 지진발생기구에 의하면, 이 지진은 거의 동서방향의 압축응력장에 주향이동성분이 가미되어 발생한 것을 암시한다. 지진원 요소들은 단주기 및 장주기 P파에 대한 원지장 스펙트럼으로부터 계산되었다. 지진모멘트(M0), 코너주파수(f0), 지진원 반경(r) 및 응력강하량($\Delta$$\sigma$)은 각각 M0 = 3.18$\times$1024 dyne-cm, f0=0.3 Hz, r=3.7km, $\Delta$$\sigma$=27bar로 구해졌다. 지진모멘트로부터 산정한 모멘트 규모는 5.6으로 나타났다.

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Manbridge Crane의 지진해석에 관한 연구

  • 윤정방;박창호
    • Computational Structural Engineering
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    • v.4 no.4
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    • pp.24-28
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    • 1991
  • 본 연구용역에서는 반도기계주식회사의 의뢰에 의거하여 Manbridge Crane의 지진하중에 대한 구조물의 안전성을 평가하였다. 구조해석은 유한요소 모형을 사용하여 사하중, 활하중 및 OBE(Operating Basis Earthquake)와 SSE(Safe Shut-down Earthquake)의 지진하중에 관한 해석을 수행하였다. Crane설치지점의 층응답스펙트럼을 입력으로 한 응답스펙트럼해법으로 지진해석을 수행하였다. Trolley의 위치와 정격하중의 유무에 따라서 5개의 구조모형을 작성하여 해석을 수행하였으며, 지진해석에는 35개의 자유진동모드가 고려되었다. 구조해석을 통하여 1) 구조부재의 과도응력 발생여부, 2) 보강재의 좌굴 가능성, 3) Hoist Rope의 안전성, 4) Crane의 전도의 가능성 및 Seismic Lug의 안전성, 5) 지진하중에 대한 제동력, 6) Crane의 주행 Rail로부터의 탈선여부, 7) Traversing Rail의 수직처짐, 8) 주행 Rail 및 End Stopper의 Anchor Bolt의 안정성, 9) Fuel Basket과 Handrail의 안전성을 검토하였다. 해석결과를 바탕으로 설계시방서에서 제시한 모든 설계요구조건을 만족시킬 수 있도록 수직 Frame의 보강부재를 보강하고, Hoist Rope 용량을 증가시키도록 제안하였다.

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