SITE ASSESSMENT AND EVALUATION OF SPATIAL EARTHQUAKE GROUND MOTION OF KYEONGJU AND HONGSUNG IN KOREA

摘要

Site characterizations were performed at Kyeongju and Hongsung for the evaluation of earthquake ground motion. Kyeongju basin was formed with a fluvial deposit by the Hyeongsan River and its small branches, while Hongsung basin was formed with a weathered residual soil on bedrock. In both sites, in-situ tests such as boring investigations, crosshole, downhole and SASW tests, and laboratory tests including resonant column tests were performed to assess the site characteristics. The shape of basin, soil profiling, shear wave velocity profiles and the dynamic properties of site materials were determined. The ground motion potentials were determined based on equivalent linear analysis based on the earthquake records scaled to the CLE and OLE of the region with the obtained ground information on both sites. The peak ground accelerations range between 0.141g and 0.366g on CLE and between 0.050g and 0.129g on OLE, respectively, showing convincing potential of amplification in the deep soil layers on bedrock which is common in Kyeongju and Hongsung basin. Ground accelerations determined by the analyses were interpreted using the GIS tool and the evaluated response spectra and site amplification factors at short and mid periods were compared with those specified in the Korean seismic design guide.