Abstract
The seismic source considered in seismic design have become more diverse and large-scale in recent years, and improving the accuracy of strong ground motion prediction near the seismic source of large-scale earthquakes is an important issue for future seismic design. In this study, we estimated the basement ground motions equivalent to Vs = 2100 m/s at the observation sites near the seismic source of the 2023 Turkey-Syria earthquake based on the diffuse field concept. The PGA and PGV of the estimated basement ground motions are almost within the variation of the ground motion model by Morikawa and Fujiwara (2013), and the seismic motion level is reduced compared to the surface records. The estimated basement ground motions are generally reasonable based on multiple verifications, except for certain sites where unusually large amplification of short-period seismic motion has been confirmed. The estimated basement ground motions and the attenuation characteristics of each period of the ground motion model showed good correspondence within the range of variation, indicating that the ground motion model may be able to evaluate large-scale, near the seismic source ground motion with a certain accuracy.
