A Review and Some New Issues on the Theory of the H/V Technique for Ambient Vibrations

Abstract

In spite of the Horizontal-to-Vertical Spectral Ratio (HVSR or H/V) technique obtained by the ambient vibrations is a very popular tool, a full theoretical explanation of it has been not reached yet. A short excursus is here presented on the theoretical models explaining the H/V spectral ratio that have been development in last decades. It leads to the present two main research lines: one aims at describing the H/V curve by taking in account the whole ambient-vibration wavefield, and another just studies the Rayleigh ellipticity. For the first theoretical branch, a comparison between the most recent two models of the ambient-vibration wavefield is presented, which are the Distributed Surface Sources (DSS) one and the Diffuse Field Approach (DFA). A mention is done of the current developments of these models and of the use of the DSS for comparing the H/V spectral ratio definitions present in literature. For the second research branch, some insights about the connection between the so-called osculation points of the Rayleigh dispersion curves and the behaviour of the H/V curve are discussed.

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

“…No strong evidence supports that the peak amplitude indicates the amplification factor of the site and there is some controversy about the nature of the ambient noise wave field and its sources (Sánchez-Sesma et al, 2011). During the past few decades, two research branches have formed to interpret the ambient noise wave field: Rayleigh wave ellipticity (Fäh et al, 2001;Wathelet et al, 2004) and the full wave-field assumptions, including distributed surface sources (DSSs, Lunedei and 798 P. Yan et al: Antarctic ice sheet thickness estimation Albarello, 2009Albarello, , 2010 and diffuse field assumption (DFA, Shapiro and Campillo, 2004;Sánchez-Sesma and Campillo, 2006;Sánchez-Sesma et al, 2011;García-Jerez et al, 2013. To calculate the H / V spectrum, a specialized GEOPSY program was developed by the European SESAME team, and widely used to investigate sediment structures (Bard and SESAME Team, 2005).…”

“…2) can be computed with provided medium properties including primary-and shear-wave velocities. The detailed formulations are not stated here on account of space limitations, but interested readers may refer to Sánchez-Sesma et al (2011), Lunedei and Malischewsky (2015), and García-Jerez et al (2016). Thus, Eq.…”

The inversion of spectral ratio H/V in a layered system using the diffuse field assumption (DFA)

“…The DFA has strong theoretical links with deterministic problems (Sánchez-Sesma et al 2011b). Lunedei and Malischewsky (2015) suggest that further investigations are required to clarify the differences between DFA and DSS.…”

“…On the other hand, Sánchez-Sesma et al (2010;2011a) have proposed recently that microtremors form a Diffuse Field containing all types of body (P and S) and surface waves (Love and Rayleigh). In a recent review, Lunedei and Malischewsky (2015) made a detailed description of the various theoretical models for the H/V spectral ratio developed in the last three decades. They identify two main research lines: ones attempt to describe the H/V curve by taking into account the complete seismic ambient-vibration wave field.…”

Some properties of Green's functions for diffuse field interpretation

“…Recently, a review of H=V theory where its applicability is discussed is given in [11]. The authors made a thorough description of the various theoretical models explaining the H=V spectral ratio that has been developed in the last three decades.…”