• Title, Summary, Keyword: 한반도 지진활동

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Seismic Characteristics of Tectonic Provinces of the Korean Peninsula (한반도 주요 지체구조구별 지진학적 특성)

  • Lee, Kie-Hwa;Kim, Jung-Ki
    • Journal of the Korean Geophysical Society
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    • v.3 no.2
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    • pp.91-98
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    • 2000
  • The seismicity of the Korean Peninsula shows a very irregular pattern of strain release typical of the intraplate seismicity. The Korean Peninsula may be divided into several tectonic provinces of differing tectonics. In this analysis, seismicity parameters for each tectonic province are evaluated from historical as well as instrumental earthquake data of the Korean Peninsula to examine the differences in seismic characteristics among tectonic provinces. Statistical analysis of the earthquake data made of incomplete data before the Choseon Dynasty and complete data afterwards reveals that there exist no significant differences in seismic characteristics between the tectonic provinces. It turns out the b-value in the intensity-frequency relation for the whole peninsula is about 0.6 and the maximum earthquake is about MMI X. The results of this study may be used in the probabilistic seismic hazard analysis of the Korean Peninsula and in estimating the design earthquake in earthquake engineering.

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Historical earthquake data of Korean (한반도의 역사지진자료)

  • Lee, Gi Hwa
    • Journal of the Korean Geophysical Society
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    • v.1 no.1
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    • pp.3-22
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    • 1998
  • Korea boasts of abundant historical earthquake records of almost 1900 events. The epicenters and intensities of these earthquakes are determined on the basis of descriptions and felt areas of the events. It turns out that most of the earthquakes occurred on major faults or tectonic boundaries of the peninsula except for the northeastern part which had been the least disrupted by tectonic disturbances during the Mesozoic. It appears that the crustal layers of the southern and northwestern parts of the peninsula had been severely ruptured during the Mesozoic disturbances and some of the faults thus generated have been active since. The seismicity of the peninsula had been rather low from the first to the fourteenth century, but unusually high from the fifteenth to the eighteenth century, and have been rather low since. This period of unusually high seismicity of the peninsula coincides with that of the northeastern part of China, suggesting the two areas are seismologically closely connected. It appears that most of the seismicity of the peninsula results from the high stress propagating from the Himalayas where the Eurasian and Indian plates collide. The data file of Korean historical earthquakes is not yet complete and supplementary studies are under way. The main purpose of this paper is to provide the data file of Korean historical earthquakes analyzed up to date for geoscientists and engineers in need of this file.

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Seismicity of the Korean Peninsula and Its Vicinity (한반도와 그 인접지역의 지진활동(地震活動))

  • Kim, So Gu
    • Economic and Environmental Geology
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    • v.13 no.1
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    • pp.51-63
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    • 1980
  • The seismicity of the Korean Peninsula and its vicinity is investigated temporally (2 A. D. to 1978) and spatially to evaluate the seismic risk and to understand the neotectonics around the peninsula. The study has been conducted using macrocosmic data obtained from historical literature, and instrumental records recorded by the Worldwide Network of Standardized Seismographs(WWNSS). The seismicity of the peninsula was active from the 13th through the 17th centuries. A seismic quiescence began at the onset of the 18th century, and has continued for the last 200 years. Presently, the seismicity region is found to be active again. The return periods are determined by a statistical method based upon the cumulative magnitude recurrence. They indicate that the seismic risk is greater in the south or west than in the north or east of the peninsula. Focal mechanism solutions demonstrate that the neotectonic stress distribution in the Japan Sea is greatly influenced by the subduction of the Pacific Plate under the Eurasian Plate or the Philippine Sea Plate, even though the predominate local paleotectonics is controlled by the spreading of the earth's crut.

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Low Frequency Lg Attenuation Coefficient around the Korean Peninsula (한반도 지역의 저주파 Lg파 감쇠상수)

  • Chung, Tae-Woong;Chung, Kyung-Hoon
    • Journal of the Korean earth science society
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    • v.32 no.1
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    • pp.152-157
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    • 2011
  • Lg amplitude decrease $Q^{-1}$ becomes very important when harzadous earthquakes occurred in neighbor nations such as Japan and China because the Lg phase is the largest seismic phase in Korea. The values of Lg $Q^{-1}$ are correlated with seismic activities from the RTSM for IRIS data with long pair distance of stations and events. The Japanese paths crossing the East Sea (Sea of Japan) show high $Q^{-1}$ values related with seismicity and oceanic crust. The paths of Shanghai having the moderate seismicity show the second highest values followed by the Japanese region, while the paths between Manchuria and the Korean Peninsula exhibit low values associated with the low seismicity of the regions.

Seismotectonic zoning by K-means clustering analysis in the Korean Peninsula (K-평균 군집분석에 의한 한반도에서의 지진지체구조구 구분)

  • Kim, Sung Kyun;Jeon, Jeong Soo;Jun, Myung-Soon
    • Journal of the Geological Society of Korea
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    • v.53 no.5
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    • pp.703-714
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    • 2017
  • It is not easy to identify seismic source zone for use in probabilistic seismic hazard analysis in the intraplate region. There is no unique formal procedure for developing and evaluating seismic source models. The K-means cluster analysis is applied to seismicity data as a point source to delineate seismotectonic model for the Korean Peninsula in this study. The number of clusters K determined by KL index and Elbow methods appears to be five and nine, respectively. A seismotectonic model composed of five source zones is developed and an alternative model with nine zones is also proposed. Seismicity parameters estimated in each zone are presented.

Intensity Attenuation in the Sino-Korea Craton (Sino-Korean 지괴에서의 진도감쇠)

  • 이기화
    • Proceedings of the Earthquake Engineering Society of Korea Conference
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    • pp.27-31
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    • 1999
  • 진도의 거리에 따른 감쇠양상은 두가치 측면에서 중요하다. 첫째는 역사지진의 크기를 평가하는데 사용되고 둘째는 역사지진자료를 이용하여 지진위험도를 평가하는데 이용된다. 한반도의 경우 대부분의 지진활동 자료가 역사지진이므로 이지진들의 크기를 결정하고 이들을 이용하여 지진위험도를 평가하기 위하여 합리적인 진도감쇠양상의 결정은 매우 중요한 과제라 할수 있다 진도의 감쇠양상은 진앙진도와 진앙거리 등 두요소에 같이 의존함이 알려져 있으므로 한반도에서 MMI VIII만의 지진자료를 이용하여 결정된 Lee의 기존의 감쇠공식은 그 사용범위에 한계가 불가피하므로 상기 두 가지 요소를 함께 고려한 새로운 감쇠공식의 유도가 요구되어진다. 지체구조적으로 Sino-Korean 지괴라고 불리우는 중국 북동부와 한반도에서 발생한 MMI VIII-X 지진들의 자료를 이용하여 한반도에서 발생하는 MMI VIII-X의 강진들에 대한 새로운 진도감쇠양상을 결정하였다.

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Some Characteristics of Seismicity and Stress State in the Korean Peninsula Using the Korean Seismic Data of the Past and the Present (과거 및 현재 지진 Data로부터 한반도 지진활동과 응력 상태)

  • 오충량;김소구;고복춘
    • The Journal of Engineering Geology
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    • v.5 no.3
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    • pp.309-329
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    • 1995
  • Seismicity and stress state in the Korean peninsula are studied using the catalogue of historical earthquakes and that from the seismological observations before the 1960s, with the aid of instrumental catalogue up to 1995. It seems that the completeness of the historical catalogue has a significant enhancement during the first two hundred years of the Yi dynasty, i.e., from the 1400s to the 1600s. From then on the catalogue may be regarded as near to complete for strong earthquakes in an overall sense. From the distribution of strong earthquakes, three seismic zones may be identified. From the south to the north, those are the southern seismic zone (남부지진대), the Seoul-Pyongyang seismic zone (서울-평양지진대), and the northern seismic zone (북부지진대). The mechanisms of some earthquakes obtained using first motion read- ings are reevaluated with a grid testing method. The results indicate that the compressional axis is nearly horizontal along the EW direction.

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Comments on Seismicity and Crustal Structure of the Korean Peninsula (한반도의 지진활동과 지각구조)

  • Lee, Kie-Hwa
    • Geophysics and Geophysical Exploration
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    • v.13 no.3
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    • pp.256-267
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    • 2010
  • Earthquakes in the Korean Peninsula occur along the faults formed and boundaries between major geological units ruptured due to violent tectonic activities during the Mesozoic. E-W and/or ENE-SSW compressive stress regime resulting from collisions between the Eurasian plate and neighbouring the Indian plate, the Pacific plate and the Philippine plate trigger Korean earthquakes of thrust faulting with predominant strike-slip components along the mostly NNE-SSW trending active faults. Seismicity of the Korean peninsula has been moderate to low during the past 20 centuries except for the period from the 15th to the 18th centuries of exceptionally high seismicity, showing the typical irregularity of intraplate seismicity. The structure of the Korean peninsula is rather homogeneous without the Conrad discontinuity sharply dividing the upper and lower crust. Lateral heterogeneities exist in the crust. The crust with an average thickness of about 33 km is thicker in the mountainous region than the plain due to the Airy-type isostatic equilibrium maintained in the peninsula. Crustal P-wave velocity with average of about 6.3 km/sec increases gradually from the near surface to the Moho. The upper mantle P-wave (Pn) velocity is about 7.8 km/sec.

Minimum magnitudes of earthquake catalog of Korea Meteorological Agency for the estimation of seismicity parameters (지진활동 매개변수 추정을 위한 기상청 지진목록의 최소규모 분석)

  • Noh, Myung-Hyun;Lee, Sang-Kook;Choi, Kang-Ryong
    • Journal of the Korean Geophysical Society
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    • v.3 no.4
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    • pp.261-268
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    • 2000
  • Minimum magnitudes $(M_c)$ for estimation of seismicity parameters were analyzed for the earthquake catalog of Korea Meteorological Agency (KMA). The temporal variation of earthquake frequency suggests that a proper $M_c$ be 3.0 for the whole southern part of the Korean Peninsula. The b-value with $M_c$ of 3.0 is estimated to be 1.11, which is larger than those of the previous studies. To see the spatial variation of $M_c$, the southern part of the peninsula were divided into grids of $0.1{\times}0.1$ degree. At the greater portion of grid points, the local earthquake catalogs do not satisfy given statistical criteria. The grid points whose local earthquake catalogs meet the criteria mostly distribute in the eastern part. $M_c$ at these points range 2.4 to 3.5 and b values range 0.75 to 1.73 with the average of 1.08 which is comparable to that for the whole southern part of the peninsula.

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