Estimating VS30 at Korean Peninsular seismic observatory stations using HVSR of event records.

The V S 30 of 89 stations in Republic of Korea are predicted using semi-empirical relationship between natural frequency (f p) selected from horizontal-to-vertical spectral ratio (HVSR) and time averaged shear wave velocity down to 30 m depth (V S 30). The installation of seismic stations has been accelerated in Republic of Korea after two damaging earthquakes at 2016–2017, but the majority of stations do not have geophysical investigation yet, and even for a few stations the investigation is prohibited due to deforestation issue and civil complaints. The objective of this study is to predict V S 30 for stations without investigation using f p to V S 30 relationship. The HVSR of 48 stations with measured V S 30 are analyzed to find appropriate f p selection and the best-fitted model. We found that the f p - V S 30 relationship is weak if the peak is not distinct and HVSR amplitude is low, and the model developed for the stable continent region fits the best. • V S 30 of 92 seismic stations located on surface in South Korea are newly estimated. • F p from HVSR is highly correlated to V S 30 if it is defined from a distinct peak with high HVSR amplitude. • F p -V S 30 relationship for Korean stations is similar to the relationship developed for Central and Eastern North America. • The standard deviation of residuals is lower than those by proxy-based methods. [ABSTRACT FROM AUTHOR]