Most of the drinking water dams managed by the local governments in Korea are earthfill dams, and these dams have almost no geotechnical property information necessary for seismic performance evaluation. Nevertheless, in the rough planning stage for improving seismic safety for these dams, it is necessary to classify their relative seismic hazard against earthquakes and conduct an additional ground investigation. The zero seismic failure probability curve is a curve suggested in this study in which the probability of failure due to an earthquake becomes ‘0’ regardless of the geotechnical properties of the earthfill dam. By examining the method and procedure for calculating failure probability due to an earthquake suggested in previous researches, the zero seismic failure probability curves for an earthquake in 1,000-year and 2,400-year return periods in Korea were presented in the form of a hyperbola on the plane of the dam height versus freeboard ratio (ratio of freeboard to dam height), respectively. The distribution characteristics of the dam height and the freeboard ratio of 81 Korean earthfill dams were presented. The two proposed zero seismic failure probability curves are shown on the plane of the dam height versus freeboard ratio, and the relative seismic hazard of 81 dams can be classified into three groups using these curves as boundaries. This study presented the method of classifying the relative seismic hazard and the classification result.

ABSTRACT
1. 서 론
2. 대상댐 특성 분석
3. 식수전용 흙댐 지진파괴확률 영곡선 도출 및상대적 지진위험도 분류
    3.1 기존 흙댐의 지진시 파괴확률 산정 방법 및 검토
    3.2 식수전용 흙댐 지진위험도 분류 지진파괴확률 영곡선 도출
    3.3 식수전용 흙댐의 상대적 지진위험도 분류
4. 결 론
REFERENCES

• 하익수(경남대학교 건설시스템공학과 교수) | Ha, Ik-soo (Professor, Department of Civil Engineering, Kyungnam University) Correspondence author