Fig. 13

a Comparison of peak frequencies between S-to-B spectral ratios for horizontal components (H-to-H) and horizontal-to-vertical (H-to-V) spectral ratios at the surface for weak-motions. b Comparison of DNL values based on S-to-B spectral ratios for horizontal components (H-to-H) and H-to-V spectral ratios at the surface. c Comparison of peak frequencies between S-to-B spectral ratios for horizontal components (H-to-H) and H-to-V spectral ratios at the surface for strong-motions. The data points are color-coded by DNL values based on the S-to-B spectral ratios. Some data points that deviate largely from the diagonal lines are provided with their site codes near the data points