A theoretical investigation of average H/V ratios

By D. Fäh, F. Kind, Domenico Giardini. 2001

502 citations recorded by the source corpus.

SUMMARY The mode summation method and a finite difference technique are applied to investigate the spectral ratio between the horizontal and vertical components (H/V ratio) of ambient vibrations and to explore the variation of the resonance frequency and the amplitude and shape of polarization as a function of the structure and the source positions. Layered structural models are used by assuming a large number of sources distributed around a receiver, with shallow source depths that are randomly assigned. We identify stable parts of the H/V ratios that are independent of the source distance and are dominated by the ellipticity of the fundamental-mode Rayleigh wave in the frequency band between the fundamental frequency of resonance of the unconsolidated sediments and the first minimum of the average H/V ratio. The ellipticity in this frequency band is determined by the layering of the sediments. The numerical simulations are compared with observations at a site where the thickness and velocity structure of the unconsolidated sediments are known from S-wave and surface wave measurements. Two methods are applied to compute the H/V ratio, the classical method in the frequency domain and a method based on frequency–time analysis that allows us to locate P–SV wavelets in the time-series. The main problem in comparing synthetics with observations is the contribution of SH waves in the observed H/V ratios. We propose a method to minimize these effects and the effects of the superposition of different incoming P–SV waves. An inversion scheme is applied to the stable parts of the observed H/V ratio, based on a genetic algorithm, to retrieve the S-wave velocity structure from a single ambient vibration record.

Subfields: Geophysics, Oceanography

View Paper: https://www.semanticscholar.org/paper/94fb47c563a8c136a176cbc34f115e9e26039aab

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In Geophysics

Citations in the corpus

Epistemic uncertainty and limitations of the κ0 model for near-surface attenuation at hard rock sites (2015, background): “In addition to direct estimates of amplification, the absence of spectral peaks in horizontal to vertical (H/V) spectral ratios also confirmed that limited amplification would be present at these sites (Fäh et al. 2001).”
H/V ratio: a tool for site effects evaluation. Results from 1-D noise simulations (2006, unknown): “On the other hand, if the shape of the H/V curves is controlled by the polarization of fundamental Rayleigh waves (Lachet & Bard 1994; Kudo 1995; Bard 1998; Konno & Ohmachi 1998; Fäh et al. 2001), then only an indirect correlation between the H/V peak amplitude and the site amplification may exist.”
Joint inversion of phase velocity dispersion and H/V ratio curves from seismic noise recordings using a genetic algorithm, considering higher modes (2005, unknown): “Likewise, single station measurements at the surface and in boreholes allow deriving S-wave velocity profiles by inverting horizontal-to-vertical spectral ratios (H/V) [e.g., Fäh et al., 2001; Tokimatsu et al., 1991; Arai and Tokimatsu, 2004].”
Exploring the model space and ranking a best class of models in surface-wave dispersion inversion: Application at European strong-motion sites (2012, background): “…to retrieve a VS profile (Scherbaum et al., 2003; Parolai et al., 2005; Fäh et al., 2009), with the H/V curve theoretically related to the Rayleigh wave ellipticity of the fundamental mode (Fäh et al., 2001; Malischewsky and Scherbaum, 2004; Bonnefoy-Claudet et al., 2006; Hobiger et al., 2009).”