Seismic Hazard Assessment for the Korean Peninsula

Abstract

ABSTRACT The Korean Peninsula is located in a stable intraplate region with low-seismicity rates and long recurrence intervals of major earthquakes. Recent moderate-size earthquakes demonstrate possible occurrence of seismic damages in the Korean Peninsula. A probabilistic seismic hazard analysis based on instrumental and historical seismicity is applied for the Korean Peninsula. Three seismotectonic province models are used for area sources. Seven ground-motion prediction equations calibrated for bedrock condition are considered. Fault source models are not applied due to poor identification of active faults. A 500 yr long historical record of earthquakes includes moderate and large earthquakes of long recurrence intervals. The influences of model parameters are reflected through a logic-tree scheme. The process and results are verified by Monte Carlo ground-motion level simulation and benchmark tests. Relatively high-seismic hazards are modeled in the northwestern, south-central, and southeastern Korean Peninsula. The horizontal peak ground accelerations reach ∼0.06, 0.09, 0.13, 0.21, and 0.28g for periods of 25, 50, 100, 250, and 500 yr, respectively, with exceedance probability of 10%. Successive moderate-size earthquakes since the 11 March 2011 Tohoku–Oki megathrust earthquake have temporarily increased the seismic hazards in the southeastern peninsula.