Seismic hazard analysis in low and moderate seismic region-Korean peninsula

Abstract

In low and moderate seismic regions, seismic activities have not been well defined. Unexpected large future earthquakes might occur in these regions, and structures can be severely damaged and collapsed since most structures in these regions were designed by considering only gravity loads. The objective of this study is to construct a uniform hazard response spectrum (UHRS) and to generate synthetic uniform hazard ground motions at a site with low and moderate seismicity for evaluating seismic performance of structures located at the site. The Seoul city hall was chosen as a site to simulate ground motions and construct a UHRS. To achieve this objective, this study simulates the epicenters and magnitudes of future earthquakes within 50,000 years based on those of past earthquakes recorded during the last 614 years. This study assumes that the site is affected only by earthquakes that occur within 100 km from the site. For 50,000 years, 36,645 earthquakes occur on the Korean peninsula, of which 4288 occur within 100 km of the selected site. Thus, 4288 ground motions are generated at the site considering earthquake attenuation and soil profiles at the site. Then uniform hazard response spectra (UHRS) are constructed at the site for 10% and 2% probabilities of exceedance over the next 50 years. This study also selects 10 ground motions for a response history analysis of structures, which best fit the UHRS.