• Title, Summary, Keyword: Odaesan earthquake

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A Study for Earthquake Parameter of Odaesan Earthquake (오대산지진(2007/01/20)의 지진원 특성에 관한 연구)

  • Kim, Jun-Kyoung
    • The Journal of Engineering Geology
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    • v.17 no.4
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    • pp.673-680
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    • 2007
  • The seismic source parameters of the Odaesan earthquake on 20 January 2007, including focal depth, focal mechanism, magnitude, and source characteristics, are analysed using seismic moment tensor inversion. The Green's function for different 3 crust models representing the southern Korean Peninsula are used. Final results show that the event, considering 6 seismic moment tensor elements, is caused by the typical strike slip fault with nearly NNE strike. The focal depth is estimated to be about 11km and 6 seismic moment tensor elements with 7.2% CLVD value shows typical double couple seismic source. The consistent characteristics of the strike and epicenter of the event with Odaesan fault imply that Odaesan earthquake is mainly caused by movement of the Odaesan fault.

Earthquake Observation through Groundwater Monitoring: A case of M4.9 Odaesan Earthquake (지하수 모니터링을 통한 지진 감시 가능성: 중규모(M4.9) 오대산 지진의 관측)

  • Lee, Hyun-A;Kim, Min-Hyung;Hong, Tae-Kyung;Woo, Nam-C.
    • Journal of Soil and Groundwater Environment
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    • v.16 no.3
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    • pp.38-47
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    • 2011
  • Groundwater monitoring data from the National Groundwater Monitoring Stations, a total of 320 stations, were analyzed to identify the response of water level and quality to the Odaesan earthquake (M4.9) occurred in January 2007. Among the total of eight stations responded to the earthquake, five wells showed water-level decline, and in three wells, water level rose. In terms of recovery, water levels in four stations had recovered to the original level in five days, but not in the rest four wells. The magnitude of water-level change shows weak relations to the distance between the earthquake epicenter and the groundwater monitoring station. However, the relations to the transmissivities of monitored aquifer in the station with the groundwater change were not significant. To implement the earthquake monitoring system through the groundwater monitoring network, we still need to accumulate the long-term monitoring data and geostatistically analyze those with hydrogeological and tectonic factors.

Spectral Features of Seismic Wave Propagation from Odaesan Earthquake (M=4.8, '07. 1. 20) (오대산지진(M=4.8, '07. 1. 20)의 지진파 전달특성 평가)

  • Yun, Kwan-Hee;Park, Dong-Hee;Chang, Chung-Joong
    • 한국지구물리탐사학회:학술대회논문집
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    • pp.81-86
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    • 2007
  • Spectral features of the seismic wave propagation from Odaesan Earthquake were evaluated based on the commonly treated random error between the observed data and the prediction values by the stochastic point-source ground-motion spectral model regarding the source, path and site effects. 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 Q0 map which are indicatives of seismic boundaries.

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The Behaviors of Earthquake Monitoring System for Gyungbu High Speed Railroad on the Odaesan Earthquake (오대산지진 시 경부고속철도 지진감시시스템 거동)

  • Kim, Dae-Sang;Kim, Sung-Il;Choi, Su-Hyun;You, Won-Hee
    • 한국방재학회:학술대회논문집
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    • pp.537-540
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    • 2008
  • This paper reviews the operation standards and manuals of earthquake monitoring system for Gyungbu high speed railroad. The domestic earthquake monitoring system detects the acceleration data at the locations of lower part of pier and deck of viaducts and bridges, not like foreign system to do the surface ground accelerations. For the purpose of evaluating the behaviors of the domestic earthquake monitoring system, measured acceleration data on the Odaesan earthquake at Iwon viaduct were analysed. The values of maximum acceleration level of the viaduct were increased from 0.0089g(EW component) of the lower part of pier to 0.014g(EW component) on the deck of the viaduct. And also the predominant periods and frequencies were analysed by the frequency domain analysis.

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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.

Large Ground Motion Related to Crustal Structure in Korea (한반도 지각 구조로 인한 이상 강진동 관측 및 해석)

  • Kim, Kwang-Hee;Kang, Su-Young;Min, Dong-Joo;Suk, Bong-Chool;Ryoo, Yong-Gyu
    • Journal of the Korean earth science society
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    • v.29 no.7
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    • pp.559-566
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    • 2008
  • Ground shaking recorded during the January 20, 2007, $M_L$ 4.8 Odaesan earthquake (Korea) were used to investigate the role of the crustal structure in producing a strong ground motion, which includes the identification of the phases responsible for the strong ground motion and their implications for seismic hazard assessment. Analyses of strong-motion data together with waveform simulation revealed that critical and post-critical reflections from the crust-mantle boundary are responsible for the abnormal ground motions. This result demonstrates that the crustal structure should be taken into consideration in studies of seismic hazard mitigation even in the areas of relatively low seismicity.

Earthquake Loss Estimation of the Gyeongju Area using the Deterministic Method in HAZUS (HAZUS의 결정론적 방법을 이용한 경주지역의 지진재해예측)

  • Kang, Su-Young;Kim, Kwang-Hee;Suk, Bong-Chool;Yoo, Hai-Soo
    • 한국방재학회:학술대회논문집
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    • pp.597-600
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    • 2008
  • Observed ground motions from the January 2007 magnitude 4.9 Odaesan earthquake and the events occurring in the Gyeongsang provinces are compared with the previously proposed ground attenuation relationships in the Korean Peninsula to select most appropriate one. The selected relationship from the ones for the Korean Peninsula has been compared with attenuation relationships available in HAZUS. Then, the attenuation relation for the Western United States proposed by Sadigh et al.(1997) for the Site Class B has been selected for this study. It has been used for the earthquake loss estimation of the Gyeongju area located in southeast Korea using the deterministic method in HAZUS with a scenario earthquake (M=6.7). Application of the improved methodology for loss estimation in Korea will help decision makers for planning disaster responses and hazard mitigation.

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Preliminary Design of Retrofitted System of Domestic Subway Tunnel (도시철도 개착식 터널의 내진성능보강시스템 기본설계)

  • Shin, Hong-Young;Kim, Doo-Kie;Kwon, Min-Ho;Chang, Chun-Ho;Kim, Ki-Hong
    • Proceedings of the KSR Conference
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    • pp.6-9
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    • 2009
  • The occurrence rate of the earthquake more than magnitude 5 has been increased since 1990 and the damage of the Odaesan earthquake, 2007 was serious. Due to that, one may say that Korea is not any more safe for the earthquake. Therefore, it is necessary to prepare strategies for possible damage due to strong earthquakes in future. This study is to focus to develop the retrofitting system for the cut and cuver tunnels built without earthquake type load scenario, so that it can provide the safety of existing urban subway system against earthquakes.

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Relation of Intensity, Fault Plane Solutions and Fault of the January 20, 2007 Odaesan Earthquake (ML=4.8) (2007년 1월 20일 오대산 지진(ML=4.8)의 진도, 단층면해 및 단층과의 관계)

  • Kyung, Jai-Bok;Huh, Seo-Yun;Do, Ji-Yong;Cho, Deok-Rae
    • Journal of the Korean earth science society
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    • v.28 no.2
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    • pp.202-213
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    • 2007
  • The Odaesan earthquake $(M_L=4.8)$ occurred near Mt. Odae, Jinbu-Myon, Pyongchang-Gun, Kangwon Province on January 20, 2007. It has a shallow focal depth about 10 km. Its felt area covers most of the southern peninsula except some southern and western inland area. The maximum MM intensity was VI in the areas including Jinbu, Doam, Kangreung, Jumunjin, and Pyongchang. In these areas, there was a very strong shaking that caused several cracks on the walls of buildings and houses, slates falling off the roof, tiles being off the wall, things falling off the desk, and rock falling from the mountains. In order to get fault plane solutions, grid searches were performed by fitting distributions of P-wave first-motion polarities and SH/P amplitude ratios for each event. The results showed that the main shock represented right-lateral strike-slip sense and two aftershocks, reverse sense. It seems that the seismogenic fault may be the NNE-SSW trending Weoljeongsa fault near the epicenter based on the distribution of epicenters (foreshock, main shock, and aftershocks), damage area, and fault plane solution. The distribution of the epicenters indicates that the length of the subsurface rupture is estimated to be about 2 km.