한반도 지질 및 지형 자료를 이용한 지반특성 지도 작성

Abstract

Earthquake disaster highly depends on geologic site conditions such as soil properties or the bed rock properties in the upper 30 m. The average shear wave velocity in the upper 30 m defined from borehole data is generally used for classifying the site conditions. However, nation-wide site condition information is not available because of limited borehole data. In this study, we used two digital maps, geologic map and topographic map, as an alternative method for site classification of Korea on a regional scale. We used geologic age and rock type from the geologic map, and used slope and elevation data from the topographic map. The predominant site class of Korea following the guidelines of National Earthquake Reduction Program (NEHRP) is B (mainly rock). Soft sediments at sites are located near rivers or on landfills as well. When we compared our results to the borehole data, there are some differences. The discrepancy is attributed to the relatively large scale geologic map (1:250000) which may include errors of the site conditions or other factors. This preliminary site condition map of Korea provides useful basic information for the further study of regional hazard estimation, risk management, other seismological and geotechnical applications, and land use planning in developing areas.