PROBABILISTIC APPROACH FOR EVALUATION OF THE FAULT ACTIVITY IN SOUTHEASTERN KOREAN PENINSULA

   Since early 1990's, several Quaternary faults have been found in the southeastern part of the Korean peninsula with reference to fault activity. Because some of these faults could be considered a capable fault, it is 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 this study, we discuss the criteria and probabilistic approaches that are used to assess whether or not a fault is seismogenic on the basis of US NRC technique. And, we 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.

Criteria	Weight	Probability	Product
Association (M > 5)	7.0	0.1	0.7
Association (M < 5)	6.0	0.2	1.2
Crustal Extent	2.0	0.8	1.6
Brittle Slip	2.0	0.8	1.6
Multiple Reactivation	2.0	0.8	1.6
Sum of Products			6.7
Sum of weights			19.0
Probability  (Seismogenic)			0.35