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

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 and 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 horizontal-to-vertical spectral ratio was derived. In addition, a best-fitting shearwave-velocity distribution with depth, v s (z), as well as a relationship between average shear-wave velocity V ¢ s and thickness of the 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.

Antarctic ice sheet thickness estimation using the horizontal-to-vertical spectral ratio method with single-station seismic ambient noise

“…Thus, the resonance frequency of the low velocity layer is closely related to its thickness (h) via the following relationship (Ibs-von Seht and Wohlenberg, 1999;Parolai et al, 2002;Picotti et al, 2017;Civico et al, 2017):…”

Seismic hazard assessment – a holistic microzonation approach

“…Local specific relations between average shear wave velocity and predominant frequency with the basement depth can be established to enable durability in the spatial extrapolation/ interpolation of these parameters (e.g. Ibs-von Seht and Wohlenberg, 1999;Parolai et al, 2002). Figure 3 depicts such relations observed in Guwahati city.…”

Site-specific response spectra from the combination of microzonation with probabilistic seismic hazard assessment—An example for the Cologne (Germany) area

“…They consist mainly of gravel, sand and clays. The thickness of the sedimentary layer generally increases from 0 m northeast of Cologne, where the Devonian basement rocks outcrop in the Bergisches Land, to more than 1000 m west of the Erft fault system [14,16,17]. The crosssection is shown in Fig.…”

“…In an area mainly west of Cologne, nearly 400 sites have been investigated by Parolai et al [13,14,18]. Twenty of these, aligned on a nearly SW-NE oriented cross-section, are selected for this study (Fig.…”

“…Within the DFNK project, PSHA were carried out taking into account the uncertainties in the input parameters [6,7]. Other studies provided detailed microzonation of the area [13,14].…”