Uncertainty-Quantified VS​ Profiles for 100 Strong-Motion Stations and Regional Site-Parameter Maps in the Southern Korean Peninsula

Reliable shear-wave velocity (V_S​) profiles and their quantified uncertainties are essential for the robust characterization of site conditions and the accurate interpretation of seismic waveforms. This study presents uncertainty-quantified V_S​​ profiles extending from the surface to depths of approximately 1 km for 100 seismic strong-motion stations across the southern Korean Peninsula. At each site, active and passive surface-wave dispersion data were acquired via microtremor array measurements and multichannel analysis of surface waves, spanning a broad frequency range from ~1 to 10 Hz and ~5 to over 50 Hz, respectively. These datasets were jointly inverted using a trans-dimensional and hierarchical Bayesian framework, which treats the number of layers and dataset-specific error levels as unknown parameters. This approach yields an ensemble of V_S​​ profiles for each station, which inherently captures depth-dependent uncertainties. From these ensembles, key seismic site parameters, including V_S​30​, bedrock depth, and resonance frequency, were estimated with rigorous uncertainty bounds to construct a comprehensive site flatfile. The estimated profiles and parameters were validated against independent in-situ borehole data, showing high consistency within the quantified uncertainty intervals. Furthermore, we derived region-specific regression equations among the site parameters, facilitating the generation of high-resolution maps for site parameters and their associated uncertainties. These outputs provide a foundation for correcting site effects in seismic waveforms, refining site terms in ground-motion prediction equations, and supporting regional seismic hazard assessments.