Combining both processing techniques of horizontal-to-vertical spectral ratio (HVSR) and surface-to-borehole spectral ratio (SBR), using the KiK-net and K-NET database in Japan, could be used in the present study to establish relationships of V_S and resonant frequency (ff) versus depth to bedrock half-space (hh) based on the site-dependent variability. Remarkable correlations of the average VsVs of layers overlying the bedrock half-space (VS¯¯¯¯¯¯VS¯) versus hh are inversely resembling those of the ff versus hh. The maximum VS¯¯¯¯¯¯VS¯ values are 1262 m/s, 933 m/s, 842 m/s, and 568 m/s through site class of B, C, D, and E, respectively. These values of VS¯¯¯¯¯¯VS¯ are decreasing gradually resembling the Vs30Vs30 through site class of B, C, D, and E according to (NEHRP, Report FEMA 368, NEHRP, Washington, 2000). The ff versus hh regressions at KiK-net sites yield gradual decrease in the correlation coefficients (i.e., a and b) through site class of B, C, D, and E, particularly the resulted a and b from SBR technique. K-NET sites yield significant lower correlation coefficients, which could be attributed to the K-NET shallow depths (hh) and their corresponding limited ranges of (ff). Although such relationships are site-specific and highly dependent on each region’s geologic conditions, fair comparisons based on site information and site-dependent variability between previous relationships of ff versus hh in the literature and the present study relationships are showing remarkable similarities. This indicates significant importance of introducing the seismic site classification as a crucial controlling factor in establishing the previous and the present VsVs and ff versus hhnonlinear regression relationships.