• The Journal of the Acoustical Society of Korea
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• v.3 no.1
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• pp.3-8
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• 1984

By one dimensional acoustic transmission from ground to air, the author has derived the level of sound caused by earthquakes. He has also tried to assign proper values of ground acceleration to the modified mercalli intensity scale and thence earthquake sound level to the intensity scale has been deduced as L\sub M/ = 79.6+6.0M, dB, where M is the earthquake magnitude in the modified Mercalli intensity scale.

• Nuclear Engineering and Technology
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• v.50 no.6
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• pp.860-868
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• 2018

This article presents a new design of earthquake instrumentation that is suitable for quick decision-making after the seismic event at the nuclear power plant (NPP). The main objective of this work is to ensure more availability of the NPP by expediting walk-down period when the seismic wave is incident. In general, the decision-making to restart the NPP after the seismic event requires more than 1 month if an earthquake exceeds operating basis earthquake level. It affects to the plant availability significantly. Unnecessary shutdown can be skipped through quick assessments of operating basis earthquake, safe shutdown earthquake events, and damage status to structure, system, and components. Multidecision parameters such as cumulative absolute velocity, peak ground acceleration, Modified Mercalli Intensity Scale, floor response spectrum, and cumulative fatigue are discussed. The implementation scope on the field-programmable gate array platform of this work is limited to cumulative absolute velocity, peak ground acceleration, and Modified Mercalli Intensity. It can ensure better availability of the plant through integrated decision-making process by automatic assessment of NPP structure, system, and components.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 2003.03a
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• pp.23-29
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• 2003

We have developed a Web-based intensity map generation system. We describe here briefly our system that is automatically generating seismic intensity map using the informations afforded by Internet users who actually experience recent earthquake. Whenever internet survey questionnaires, reported from the citizens using the form available through our Web site, are received, the associated ZIP code region is color-coded according to the Modified Mercalli Intensity Scale. As the number of questionnaires is increased, the intensity value of each region divided by ZIP code is averaged and updated automatically. The coverage of acceleration stations is insufficient to map the accurate extent of ground shaking in Korea. So our system will serve as an alternative for much more rapid generation of intensity map than conventional method, such as mailing intensity survey or elaborate manual processing.

• Journal of the Earthquake Engineering Society of Korea
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• v.20 no.7_spc
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• pp.517-526
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• 2016

In this paper, some popular intensity measures of earthquakes including magnitude, MMI, and PGA as well as their empirical relationships are briefly reviewed since they have been widely used without prudence by mass media, the public, and even the government when asking or expressing the seismic capacity of buildings. The basic concept of current seismic design is also presented in order to facilitate relevant discussions. It is emphasized that expressing the building seismic capacity simplistically in terms of seismological quantities or terminologies like magnitude and MMI is inherently irrational, may be misleading the stakeholders, and should be avoided. Alternative expressions, more rational and consistent with current seismic design philosophy and practice, are recommended.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1997.10a
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• pp.41-48
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• 1997

The seismic risk in Seoul Metropolitan Area(latitude 37.0$^{\circ}$~37.8$^{\circ}$, longitude 126.5$^{\circ}$~127.5$^{\circ}$)based on all Korean earthquake data of Modified Mercalli Intensity equal to or greater than V is evaluated by extreme value method and point source method. The seismic risk estimated from all data turned out to be lower than from the data since the Chosen dynasty during which seismic data appear to be rather complete. The damaging earthquake of park horizontal ground acceleration grater than 0.1g turns out to occur with 90% probability of being exceeded in 200 years when the data since the Chosen Dynasty are used.

• Journal of the Earthquake Engineering Society of Korea
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• v.1 no.4
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• pp.29-35
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• 1997

The probabilistic seismic risk in Seoul Metropolitan Area $(atitude도 37.0^{circ}~37.8^{circ} N, longitude 126.5^{circ}~127.5^{circ} E)$ based on all Korean earthquake data of MM Intensity equal to or greater than V is evaluated by point source method. The seismic risk estimated from all data turned out to be lower than that from the data since the Choseon Dynasty during which seismic data appear to be rather complete. The damaging earthquake of peak horizontal ground acceleration greater than 0.1g turns out to occur with 90% probability of being exceeded in 200 years and 500 years when the data since Choseon Dynasty and all data are used, respectively.

• Korean Journal of Remote Sensing
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• v.37 no.1
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• pp.13-22
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• 2021

The ML 5.8 earthquake shocked Gyeongju, Korea, at 11:32:55 UTC on September 12, 2016. One year later, on the afternoon of November 15, 2017, the ML 5.4 earthquake occurred in Pohang, South Korea. The earthquakes injured many residents, damaged buildings, and affected the economy of Gyeongju and Pohang. The damage proxy maps (DPMs) were generated from Sentinel-1 synthetic aperture radar (SAR) imagery by comparing pre- and co-events interferometric coherences to identify anomalous changes that indicate damaged by the earthquakes. DPMs manage to detect coherence loss in residential and commercial areas in both Gyeongju and Pohang earthquakes. We found that our results show a good correlation with the Korea Meteorological Administration (KMA) report with Modified Mercalli Intensity (MMI) scale values of more than VII (seven). The color scale of Sentinel-1 DPMs indicates an increasingly significant change in the area covered by the pixel, delineating collapsed walls and roofs from the official report. The resulting maps can be used to assess the distribution of seismic damage after the Gyeongju and Pohang earthquakes and can also be used as inventory data of damaged buildings to map seismic vulnerability using machine learning in Gyeongju or Pohang.

• Geotechnical Engineering
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• v.12 no.2
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• pp.19-32
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• 1996

Based on Trifuilac's empirical model to transform earthquake acceleration time history in the time domain into Fourier amplitude spectrum in the frequency domail an earthquake scaling technique for simulating the earthquake record of certain magnitude as the required magnitude earthquake was suggested. Also, using the earthquake record of magni dude(M) 5.8, the simulated earthquake of magnitude(M) 8.0 was established and its application to dynamic testing system was proposed. The earthquake scaling technique could be considered by several terms : earthquake magnitude(M), earthquake intensity(MMI), epicentral distance, recording site conditions, component direction and confidence level required by the analysis. Albo, it had an application to the various earthquake records. The simulated earthquake in this study was established by two orthogonal horizontal components of earthquake acceleration-time history. The simulated earthquake shaking could be applied to the dynamic pile load test for the model tension pile and the model compressive open -ended piles driven into the pressure chamber. In the static pile load test, behavior of two piles was very different and after model tension pile experienced 2 or 3 successive slips of the pile relative to the soil, it was failed completely. During the simulated earthquake shaking, dynamic behavior and pile capacity degradation of two piles were very different.