Improved Holistic Analysis of Rayleigh Waves for Single- and Multi-Offset Data: Joint Inversion of Rayleigh-Wave Particle Motion and Vertical- and Radial-Component Velocity Spectra

Abstract

Abstract-Rayleigh waves often propagate according to complex mode excitation so that the proper identification and separation of specific modes can be quite difficult or, in some cases, just impossible. Furthermore, the analysis of a single component (i.e., an inversion procedure based on just one objective function) necessarily prevents solving the problems related to the non-uniqueness of the solution. To overcome these issues and define a holistic analysis of Rayleigh waves, we implemented a procedure to acquire data that are useful to define and efficiently invert the three objective functions defined from the three following ''objects'': the velocity spectra of the vertical-and radialcomponents and the Rayleigh-wave particle motion (RPM) frequency-offset data. Two possible implementations are presented. In the first case we consider classical multi-offset (and multi-component) data, while in a second possible approach we exploit the data recorded by a single three-component geophone at a fixed offset from the source. Given the simple field procedures, the method could be particularly useful for the unambiguous geotechnical exploration of large areas, where more complex acquisition procedures, based on the joint acquisition of Rayleigh and Love waves, would not be economically viable. After illustrating the different kinds of data acquisition and the data processing, the results of the proposed methodology are illustrated in a case study. Finally, a series of theoretical and practical aspects are discussed to clarify some issues involved in the overall procedure (data acquisition and processing).

The magnifying effect of a thin shallow stiff layer on Love waves as revealed by multi-component analysis of surface waves

“…Techniques are usually grouped into two main families: active (e.g. Multichannel Analysis of Surface Waves -MASW, Holistic analysis of Surface waves -HS; Frequency Time Analysis -FTAN 1, [14][15][16][17][18][19] ) and passive (e.g. f-k analysis, Spatial AutoCorrelation -SPAC, Extended Spatial AutoCorrelation -ESAC and Miniature Array Analysis of Microtremors [20][21][22][23] ).…”

Single- and multi-component inversion of Rayleigh waves acquired bya single 3-component geophone: an illustrative case study

“…The RPM frequency curve represents the correlation coefficients (frequency by frequency) between the radial component and the Hilbert transform of the vertical component. A purely retrograde motion is defined by a +1 value, whereas A further possibility that, thanks to the light field procedures and necessary equipment, can be an appealing and efficient solution, is represented by the holistic approach presented in Dal Moro (2014) and Dal Moro et al (2015bMoro et al ( , 2015cMoro et al ( , 2015dMoro et al ( , 2017a [Holistic analysis of Surface waves -HS]. This holistic methodology is an improvement of the classical Multiple Filter Analysis (MFA) technique described in Dziewonsky et al (1969) and is based on the active data recorded by means of a single 3component (3C) geophone.…”

“…1c) does not necessarily relate to a single higher mode. A series of synthetic and real data sets aimed at giving evidence of these aspects are presented in Dal Moro (2014 -Chapter 3) and Dal Moro et al (2017a).…”

“…A possible solution to these problems and ambiguities can be represented by the joint acquisition and analysis of Love waves and/or the radial component of Rayleigh waves (Safani et al, 2005;Dal Moro and Ferigo, 2011;Xia et al, 2012;Dal Moro et al, 2015b, 2016, 2017a).…”

Rayleigh‐wave dispersion analysis using complex‐vector seismic data

“…Rayleigh waves move elliptically along a radial plane in isotropic horizontal‐layer media (Dal Moro ). Therefore, they can be recorded by both radial‐ and vertical‐component geophones, in which the dispersive energy of Rayleigh waves show different distribution (Dal Moro and Ferigo ; Dal Moro, Moura and Moustafa ; Dal Moro, Moustafa and Al‐Arifi ). When using the radial and vertical components jointly, Boaga et al .…”