• Journal of the Korean earth science society
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• v.37 no.3
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• pp.162-172
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• 2016

Since the Northridge earthquake in 1994 and the Kobe earthquake in 1995 occurred, the concept of performance based design has been introduced for designing various kinds of important structures and buildings. Uniform hazard spectra (UHS), with annual exceedance probabilities, corresponding to the performance level of each structure, are required for performance-based design. The probabilistic seismic hazard analysis was performed using spectral ground motion prediction equations, which were developed from both Korean Peninsula and Central and Eastern US region, and several seismotectonic models suggested by 10 expert panel members in seismology and tectonics. The uniform hazard spectra for 5 highly populated cities in Korea, with recurrence period of 500, 1,000, and 2,500 years using the seismic hazard at the frequencies of 0.5, 1.0, 2.0, 5.0, 10.0 Hz and Peak ground acceleration (PGA) were analyzed using the probabilistic seismic hazard analysis. The sensitivity analysis suggests that spectral ground motion prediction equations impact much more on seismic hazard than what seismotectonic models do. The uniform hazard spectra commonly showed a maximum hazard at the frequency of 10 Hz and also showed the similar shape characteristics to the previous study and related technical guides to nuclear facilities.

• Proceedings of the Earthquake Engineering Society of Korea Conference
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• 1999.10a
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• pp.64-71
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• 1999

Seismicity of the Korean Peninsula shows intraplate seismicity that has irregular pattern in both time and space. Seismic data of the Korean peninsula consists of historical earthquakes and instrumental earthquakes. In this study we devide these data into complete part and incomplete part and considering earthquake size uncertainty estimate seismic hazard parameters - activity rate λ, b value of Gutenberg-Richter relation and maximum possible earthquake IMAX by statistical method in each major tectonic provinces. These estimated values are expected to be important input parameters in probabilistic seismic hazard analysis and evaluation of design earthquake.

• Earthquakes and Structures
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• v.8 no.3
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• pp.681-697
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• 2015

Iran as one of the countries located on the Alpine-Himalayan seismic belt has recently experienced a few number of catastrophic earthquakes. A well-known index of how buildings are affected by earthquakes is through assessment of probable Peak Ground Acceleration (PGA) and structures' response spectra. In this research, active faults around Kerman and Birjand, two major cities in eastern parts of Iran, have been considered. Seismic catalogues are gathered to categorize effects of surrounding faults on seismicity of the region. These catalogues were further refined with respect to time and space based on Knopoff-Gardner algorithm in order to increase statistical independency of events. Probabilistic Seismic Hazard Analysis (PSHA) has been estimated for each of cities regarding 50, 100, 200 and 500 years of structures' effective life-span. These results subsequently have been compared with Deterministic Seismic Hazard Analysis (DSHA). It has been observed that DSHA not necessarily suggests upper bound of PSHA results. Furthermore, based on spectral Ground Motion Prediction Equations (GMPEs), Uniform Hazard Spectra (UHS) and spectral acceleration were provided for 2% and 10% levels of probability of exceedance. The results show that increasing source-to-site distance leads to spectral acceleration reduction regarding each fault. In addition, the spectral acceleration rate of variation would increase if the source-to-site distance decreases.

• Journal of the Earthquake Engineering Society of Korea
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• v.2 no.3
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• pp.83-86
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• 1998

The results from the Individual Plant Examination of External Event of Yonggwyang nuclear power plants, unit 3 & 4, in Korea have shown that the high degree of diversities of the experts' opinions on seismicity and attenuation models is su, pp.sed to be generic cause of uncertainty of APEs(annual exceedance probability) in the PAHA(probabilistic seismic hazard analysis). This study investigated the sensitivity of the focal depth, which is one of the most uncertain seismicity parameters in Korea, Significant differences in resultant values of annual exceedance probabilities and much more symmetrical shape of the resultant PDFs(probability density functions), in case of consideration of focal depth, are found. These two results suggest that, even for the same seismic input data set including the seismicity models and ground motion attenuation models, to consider focal depth additionally for probabilistic seismic hazard analysis evaluation makes significant influence on the distributions of uncertainties and probabilities of exceedance per year for the whole ranges of seismic hazard levels. These facts suggest that it is necessary to derive focal depth parameter more effectively from the historical and instrumental documents on earthquake phenomena in Koran Peninsula for the future study of PSHA.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2006.04a
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• pp.473-480
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• 2006

Liquefaction of soil foundation is one of the major seismic damage types of infrastructures. In this paper, deterministic and probabilistic approaches for the evaluation of liquefaction potential are briefly summarized and the risk assessment method is newly proposed using seismic fragility and seismic hazard curves. Currently the deterministic approach is widely used to evaluate the liquefaction potential in Korea. However, the there are a certain degree of uncertainties in the soil properties such as elastic modulus and resistant capacity, therefore the probabilistic approach is more promising. Two types of probabilistic approach are introduced including (1) failure probability for a given design earthquake and (2) the seismic risk of liquefaction of soil for a given service life. The results from different methods show a similar trend, and the liquefaction potential can be more quantitatively evaluated using risk analysis method.

• Structural Engineering and Mechanics
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• v.33 no.6
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• pp.725-745
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• 2009

In this paper, probabilistic seismic performance assessment of a typical non-seismic RC frame building representative of a large inventory of existing buildings in developing countries is conducted. Nonlinear time-history analyses of the sample building are performed with 20 large-magnitude medium distance ground motions scaled to different levels of intensity represented by peak ground acceleration and 5% damped elastic spectral acceleration at the first mode period of the building. The hysteretic model used in the analyses accommodates stiffness degradation, ductility-based strength decay, hysteretic energy-based strength decay and pinching due to gap opening and closing. The maximum inter story drift ratios obtained from the time-history analyses are plotted against the ground motion intensities. A method is defined for obtaining the yielding and collapse capacity of the analyzed structure using these curves. The fragility curves for yielding and collapse damage levels are developed by statistically interpreting the results of the time-history analyses. Hazard-survival curves are generated by changing the horizontal axis of the fragility curves from ground motion intensities to their annual probability of exceedance using the log-log linear ground motion hazard model. The results express at a glance the probabilities of yielding and collapse against various levels of ground motion intensities.

• Nuclear Engineering and Technology
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• v.43 no.5
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• pp.437-446
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• 2011

Siting criteria for nuclear power plants require that faults be characterized as to their potential for generating earthquakes, or that the absence of the potential for these occurrences be demonstrated. Because the definition of active faults in Korea has been applied by the deterministic method, which depends on the numerical age of fault movement, the possibility of inherent uncertainties exists in determining the maximum earthquake from the fault sources for seismic design. In an attempt to overcome these problems this study suggests new criteria and a probabilistic quantitative diagnostic procedure that could estimate whether a fault is capable of generating earthquakes in the near future.

• Journal of the Korean earth science society
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• v.37 no.1
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• pp.52-61
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• 2016

The purpose of the study was to create a probabilistic seismic hazard map using the input data that reflected the seismo-tectonic characteristics of the Korean Peninsula by applying USGS program (Harmsen (2008). The program was partly modified for the purpose of this study. The uncertainty of input parameters given by specialists was reflected in calculating the seismic hazard values by logic tree method. The general pattern of PGA was quite sensitive and similar to the shape of areal source. The probabilistic seismic hazard map showed the contour distribution of peak acceleration (%g) with 10% probability of exceedance in 5, 10, 20, 50, 100, 250, and 500 years. The result showed that the peak ground acceleration (PGA) values of the northern peninsula were almost half values of the southern peninsula except Hwanghae province. The general trend of the hazard map extended in the direction of NW-SE from Whanghae province to south-eastern regions of the peninsula. The values in northern part of Kangwon province were relatively lower than other areas in the southern peninsula. The maps produced through this study are considered valuable in regulating the seismic safety of the major facilities in the Korean Peninsula.

• Journal of the Earthquake Engineering Society of Korea
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• v.19 no.6
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• pp.265-271
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• 2015

The tsunami hazard analysis is performed for testing the application of probabilistic tsunami hazard analysis to nuclear power plant sites in the Korean Peninsula. Tsunami hazard analysis is based on the seismic hazard analysis. Probabilistic method is adopted for considering the uncertainties caused by insufficient information of tsunamigenic fault sources. Logic tree approach is used. Uljin nuclear power plant (NPP) site is selected for this study. The tsunamigenic fault sources in the western part of Japan (East Sea) are used for this study because those are well known fault sources in the East Sea and had several records of tsunami hazards. We have performed numerical simulations of tsunami propagation for those fault sources in the previous study. Therefore we use the wave parameters obtained from the previous study. We follow the method of probabilistic tsunami hazard analysis (PTHA) suggested by the atomic energy society of Japan (AESJ). Annual exceedance probabilities for wave height level are calculated for the site by using the information about the recurrence interval, the magnitude range, the wave parameters, the truncation of lognormal distribution of wave height, and the deviation based on the difference between simulation and record. Effects of each parameters on tsunami hazard are tested by the sensitivity analysis, which shows that the recurrence interval and the deviation dominantly affects the annual exceedance probability and the wave heigh level, respectively.

• Journal of the Earthquake Engineering Society of Korea
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• v.18 no.3
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• pp.151-160
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• 2014

Probabilistic tsunami hazard analysis (PTHA) is based on the approach of probabilistic seismic hazard analysis (PSHA) which is performed using various seismotectonic models and ground-motion prediction equations. The major difference between PTHA and PSHA is that PTHA requires the wave parameters of tsunami. The wave parameters can be estimated from tsunami propagation analysis. Therefore, a tsunami simulation analysis was conducted for the purpose of evaluating the wave parameters required for the PTHA of Uljin nuclear power plant (NPP) site. The tsunamigenic fault sources in the western part of Japan were chosen for the analysis. The wave heights for 80 rupture scenarios were numerically simulated. The synthetic tsunami waveforms were obtained around the Uljin NPP site. The results show that the wave heights are closely related with the location of the fault sources and the associated potential earthquake magnitudes. These wave parameters can be used as input data for the future PTHA study of the Uljin NPP site.