New Relationships between Vs, Thickness of Sediments, and Resonance Frequency Calculated
               by the H/V Ratio of Seismic Noise for the Cologne Area（Germany）

                               by S. Parolai, P. Bormann, and C.milkereit

                                     2005/10/13 Chia-Chun Hsu

                                       Abstract

                 Noise measurements were carried out in the Cologne area (Germany),
               and the resonance frequency of each site was estimated from the main
               peak in the spectral ratio between the horizontal vertical component. For
               32 of these sites, the thickness of the sedimentary cover was known from
               boreholes, and a clear correlation between resonance frequency and
               sediment thickness was observed. A formula that correlates cover
               thickness with frequency of the main peak in the wave-velocity
               distribution with depth, vs(z), was well as relationship between average
               shear-wave velocity Vs and thickness of sedimentary cover, was
               calculated. By using all of the noise measurements and applying the
               derived relationships, we obtained a subsoil classification for the Cologne
               area.

                                      Reference:

               Al Yuncha, Z., and F. Luzon (2000). On the horizontal-to-vertical spectral 
               ratio in sedimentary basins, Bull. Seism. Soc. Am. 90, 1101-1106

                                      (Abstract)(Full text)

               Parolai, S., P. Bormann, and C. Milkereit (2002). New relationships between 
               Vs, thickness of sediments, and resonance frequency calculated by the H/V ratio
               of seismic noise for the Cologne area (Germany), Bull. Seism. Soc. Am. 92, 2521-2527

                                      (Abstract)(Full text)