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In Korea 20 nuclear power plant units are operating, 6 units are under construction and 2 units are made plan at 4 sites. The nuclear facilities require to withstanding an effect of the earthquake that may occur during their lifetime. However, it is not easy to predict accurately the potential of earthquake that may occur in their sites. Up to present because it was not discovered the Quaternary fault near the nuclear power plants in Korea, it was not considered the fault as a seismic source but has been considered only the historical earthquakes with reference to the seismic design for nuclear power plant.
Since early 1990's, several Quaternary faults have been found along the Ulsan fault, Yangsan fault and eastern coastline in the southeastern part of the Korean peninsula. Because some of these faults, which are close to nuclear power plants, could be considered a capable fault (terminology by US NRC), it has been a very delicate matter, which needs to be deal with carefully in assessing the seismic hazard for nuclear power plants.
In determining whether or not the faults are capable, because of the low rate of seismicity and insufficient relationship between instrumental macro-seismicity and fault, there has been considerable debate among geologists and geophysicists in Korea. In view of the results so far achieved, however, in spite of many research works the issue has not been fully resolved yet done.
As mentioned above it is not easy to define that the faults are active or not by the deterministic approach. In this study, therefore, I discuss the criteria, relative weight factor and probabilistic approaches that are used to assess seismogenic potential of the faults in the southeastern part of the Korean peninsula on the basis of US NRC technique. And, I preliminarily also suggest the probability of fault activity from the spatial association between faults and earthquake epicenters, fault slip and tectonic stress, and geological evidence for multiple episodes of reactivation. I expect that these results could be applied for probabilistic seismic hazard analysis in the Korean peninsula.
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