Some theoretical and numerical observations on scattering of Rayleigh waves in media containing shallow rectangular cavities

Chai, Hua-You; Phoon, Kok‐Kwang; Goh, Siang-Huat; Wei, Changfu

doi:10.1016/j.jappgeo.2012.05.005

Cited by 30 publications

(13 citation statements)

References 25 publications

(45 reference statements)

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“…To sum up, the larger the cavity compared to the wavelength, the more the energy is propagated in the forward direction. At first sight this result seems to be in contradiction with the observations carried out by Chai et al (2012). Their studies, conducted on the relationship between cavity size and wavelength led to the conclusion that back-scattering energy increases with the Si ze λ ratios.…”

Section: Discussion a N D P E R S P E C T I V E Smentioning

confidence: 70%

See 1 more Smart Citation

New robust observables on Rayleigh waves affected by an underground cavity: from numerical to experimental modelling

Filippi

Leparoux²,

Grandjean

et al. 2019

Geophysical Journal International

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The investigation and monitoring of shallow hazards due to the presence of underground cavities remain a challenge for geophysical approaches. Thus, seismic surface waves have been tested in several recent research projects in order to detect and localize voids as well as to determine their geometries. Among these works, numerous numerical studies have proved the feasibility of Rayleigh waves to detect cavities. However, most imagery processes adapted to R waves are faced with difficulties when applying them to real data. This limitation points to a major problem: the interactions between Rayleigh waves and a cavity are complex, particularly in the case of dispersing and attenuating surrounding media. Here, a combined approach based on numerical and experimental data obtained in a reduced-scale measurement bench is conducted to better understand the seismic wave propagation phenomena involved in the presence of a cavity and define robust observables that can be used in field measurements. The observables bearing the cavity signature are studied qualitatively and quantitatively on numerical and experimental recordings. The latter take into account all the propagation phenomena involved. The observations are carried out on the vertical and horizontal component of the Rayleigh wave displacement. The selected observables are studied depending on nondimensional cavity's parameters versus the frequency, that is the wavelength-to-size ratio and the wavelength-to-depth ratio. The effects of the cavity's parameters on the observables show particularities as a function of these components, such as a higher rate of the amplitude on the horizontal component as well as a perturbation of the direct seismic surface wave amplitude above the cavity, also higher on the horizontal component. This latter feature is particularly visible on the variation of the elliptical particle motion recorded at the surface. It can be linked to the mode conversions that occur in the vicinity of the cavity and which predominate on the horizontal component when the signal is normalized.

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Section: Discussion a N D P E R S P E C T I V E Smentioning

confidence: 70%

“…But, all the complex phenomena highlighted in several numerical studies (e.g. Gelis et al 2005;Xia et al 2007;Chai et al 2012;Dravinski et al 2013;Shao et al 2016)) are not taken into account for the seismic imaging. The R wave propagation is simplified and mode conversions are not part of the process.…”

Section: Introductionmentioning

confidence: 99%

New robust observables on Rayleigh waves affected by an underground cavity: from numerical to experimental modelling

Filippi

Leparoux²,

Grandjean

et al. 2019

Geophysical Journal International

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show abstract

“…Local discontinuities, due to the lateral heterogeneity beneath the seabed, e.g., submarine faults, are also visible. A portion of the propagating wavefield is backscattered around 9 km (highlighted on Fig.3a) indicating a potential laterally abrupt feature at this position [44]. Higher mode Scholte waves emerge in the off-shore section with higher frequency components and higher apparent velocities (highlighted on Fig.3b) compared with the fundamental mode in the near-shore section (Fig.3a).…”

Section: Coherent Scholte Wavefieldsmentioning

confidence: 98%

Utilizing Distributed Acoustic Sensing and Ocean Bottom Fiber Optic Cables for Submarine Structural Characterization

Cao¹,

Ajo‐Franklin²,

Chi³

et al. 2020

Preprint

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“…This subject is covered by Chai et al (2012Chai et al ( , 2014. We recommend using a synthetic data test, as the one demonstrated above, for each case where natural migration is applied to assess the abilities and the limits of the method in the given geological settings, noise distribution and survey geometry.…”

Section: Natural Migration Proceduresmentioning

confidence: 99%

Imaging Near-surface Heterogeneities by Natural Migration of Back-scattered Surface Waves

AlTheyab¹,

Workman²,

Lin³

et al. 2015

Proceedings

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Some theoretical and numerical observations on scattering of Rayleigh waves in media containing shallow rectangular cavities

Cited by 30 publications

References 25 publications

New robust observables on Rayleigh waves affected by an underground cavity: from numerical to experimental modelling

New robust observables on Rayleigh waves affected by an underground cavity: from numerical to experimental modelling

Utilizing Distributed Acoustic Sensing and Ocean Bottom Fiber Optic Cables for Submarine Structural Characterization

Imaging Near-surface Heterogeneities by Natural Migration of Back-scattered Surface Waves

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