Group A, Poster #237, Ground Motions

Prediction of ground motion in South Korea based on physics-based broadband ground motion simulation

Seokho Jeong, Sung Bae, Jae Hwi Kim, & Kwangyoung Kim
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Poster Presentation

2022 SCEC Annual Meeting, Poster #237, SCEC Contribution #12386 VIEW PDF
Korean peninsula is placed in a stable continental region (SCR). In an SCR, moderate to large earthquakes do not occur frequently. However, like many other places in SCRs, Korea has suffered from infrequent yet damaging earthquakes in the past. Among the instrumented earthquakes, the largest was the 2016 M5.5 9.12 earthquake. The 2017 M5.4 Pohang earthquake was the second largest; yet it was the most damaging earthquake, likely due to the combination of its proximity to urban areas, its shallow hypocentral depth of 5km, and amplification of ground motions within the Pohang basin. Being in a SCR with a short history of instrumentation, South Korea has not collected sufficient instrumental dat...a for data-driven ground motion models. In an attempt to address this limitation, we implemented the physics-based hybrid broadband ground motion simulation method of Graves and Pitarka (2010, 2015), by modifying the simulation platform of QuakeCoRE, to simulate earthquakes in South Korea accounting for the crustal velocity structure and seismological characteristics of the Korean peninsula. For crustal velocity models, we implemented a three-dimensional velocity model by Kim et al. (2017) and a one-dimensional velocity model by Kim et al. (2011). To generate kinematic source models, we implemented Graves and Pitarka’s rupture generator, with a magnitude-area scaling relationship developed for SCR by Leonard (2014). Using the implemented simulation platform, we successfully simulated the 2016 M5.5 9.12 earthquake and the 2017 M5.4 Pohang earthquake and compared results with recorded ground accelerations at strong motions stations. While our work demonstrated the potential of physics-based ground motion simulation in South Korea, it also suggested the need for further validation of the simulation method for earthquake engineering applications in South Korea.