• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.6
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• pp.369-378
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• 2016

The design spectrum for Korea, which is known to belong to an intra-plate region, is developed from the ground motion records of the earthquakes occurred in Korea and overseas intra-plate regions. The horizontal spectrum is defined as geometric mean spectrum, GMRotI50. From the statistical analysis of the geometric mean spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. The developed design spectrum is valid for the estimation both spectral acceleration and displacement.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.6
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• pp.413-424
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• 2016

The vertical design spectrum for Korea, which is known to belong to an intra-plate region, is developed from the ground motion records of the earthquakes occurred in Korea and overseas intra-plate regions. From the statistical analysis of the vertical response spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. The developed design spectrum is valid for the estimation both spectral acceleration and displacement. The ratio of vertical to horizontal response spectrum for each record is calculated. Statistical analysis of the ratios rendered the vertical to horizontal ratio (V/H ratio). Subsequently the ratio between the peak vertical ground acceleration to the horizontal one is obtained.

• Journal of the Earthquake Engineering Society of Korea
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• v.22 no.3
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• pp.129-137
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• 2018

On November 15, 2017, Pohang earthquake occurred. Its local magnitude was announced to be $M_L=5.4$ by Korea Meteorological Administration (KMA). Ground motion data recorded at KMA stations were obtained from their data bases. From the data, horizontal and vertical response spectra, and V/H ratio were calculated. The horizontal spectra were defined as GMRotI50 spectra. From the statistical analysis of the GMRotI50 spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. Applying the same procedure, the shape and transition periods of vertical spectrum were obtained. These results were compared with theKorean standard design spectra, which were developed from domestic and overseas intra-plate earthquake records, and Gyeongju earthquake response spectra. The response spectra of Pohang earthquake were found to be almost identical with the newly proposed design spectra. Even the V/H ratios showed good agreement. These results confirmed that the method adopted when developing the standard design spectra were valid and the developed design spectra were reliable.

• Journal of the Earthquake Engineering Society of Korea
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• v.21 no.6
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• pp.277-286
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• 2017

On September 12, 2016, Gyeongju earthquake occurred. Its local magnitude was announced to be $M_L=5.8$ by Korea Meteorological Administration (KMA). Ground motion data recorded at KMA, EMC and KERC stations was obtained from their data bases. From the data, horizontal and vertical response spectra, and V/H ratio were calculated. The horizontal spectrum was defined as geometric mean spectrum, GMRotI50. From the statistical analysis of the geometric mean spectra, a mean plus one standard deviation spectrum in lognormal distribution is obtained. Regression analysis is performed on this curve to determine the shape of spectrum including transition periods. Applying the same procedure, the shape and transition periods of vertical spectrum was obtained. These results were compared with the Korean standard design spectra, which were developed from domestic and overseas intraplate earthquake records. The response spectra of Gyeongju earthquake were found to be almost identical with the newly proposed design spectra. Even the V/H ratios showed good agreement. These results confirmed that the method adopted when developing the standard design spectra were valid and the developed design spectra were reliable.

• KIPS Transactions on Software and Data Engineering
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• v.12 no.11
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• pp.493-504
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• 2023

The Republic of Korea is located far from the boundary of the earthquake plate, and the intra-plate earthquake occurring in these areas is generally small in size and less frequent than the interplate earthquake. Nevertheless, as a result of investigating and analyzing earthquakes that occurred on the Korean Peninsula between the past two years and 1904 and earthquakes that occurred after observing recent earthquakes on the Korean Peninsula, it was found that of a magnitude of 9. In this paper, the Korean Peninsula Historical Earthquake Record (2 years to 1904) published by the National Meteorological Research Institute is used to analyze the relationship between earthquakes on the Korean Peninsula and statistical self-similarity. In addition, the problem solved through this paper was the first to investigate the relationship between earthquake data occurring on the Korean Peninsula and statistical self-similarity. As a result of measuring the degree of self-similarity of earthquakes on the Korean Peninsula using three quantitative estimation methods, the self-similarity parameter H value (0.5 < H < 1) was found to be above 0.8 on average, indicating a high degree of self-similarity. And through graph visualization, it can be easily figured out in which region earthquakes occur most often, and it is expected that it can be used in the development of a prediction system that can predict damage in the event of an earthquake in the future and minimize damage to property and people, as well as in earthquake data analysis and modeling research. Based on the findings of this study, the self-similar process is expected to help understand the patterns and statistical characteristics of seismic activities, group and classify similar seismic events, and be used for prediction of seismic activities, seismic risk assessments, and seismic engineering.

• Economic and Environmental Geology
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• v.36 no.3
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• pp.233-242
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• 2003

The southeasternmost coastal area of the Korean peninsula has been regarded as a seismologically stable area as neither Quaternary faults nor earthquake activity has been reported. To clarify whether the active tectonic movement has occurred or not, a digital marine terrace mapping and fracture mapping have been done in the coastal area. Bed rocks are composed of the Cretaceous volcanic and sedimentary rocks and the Paleogene granite. Wave-cut platform in the area is smaller and narrower relative to that of the northern coastal area. Most of the platforms in the area have little Quaternary sediment. The platforms except the Holocene terrace (1 st terrace) can be divided into three steps. The lowest platform (2nd terrace) has an altitude of 8-11 m. The broad middle one (3rd terrace) is 17 to 22 m high. The highest terrace (4th terrace) is a narrow and sporadic bench with an altitude of about 44 m high. The lowest terrace is correlated to the 2nd terrace of the northern area, which corresponds to the oxygen isotopic stage 5a. The uplift rate calculated from a graphic method is 0.19 m/ky. This low uplift is typical of an intra-plate, suggesting that the area is tectonically stable. The elevation of the platforms tends slightly lower from the north to the south in the survey area. The decreasing altitude of the platforms towards the south is interpreted to result from a local block tilting during the Latest Pleistocene. This also indicates that the eastern coast of the Korean peninsula has been suffering a subsidence to the south.