Multiple scattering of seismic waves

Tregoures, Nicolas; Hennino, R.; Lacombe, C.; Shapiro, N. M.; Margerin, Ludovic; Campillo, Míchel; Tiggelen, B. A. van

doi:10.1016/s0041-624x(02)00105-1

Cited by 9 publications

(5 citation statements)

References 24 publications

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“…The decay of the high-frequency seismic coda signal is related to the local properties of the subsurface (Trégourès et al 2002). The investigation and modelling of the decay can therefore be used to investigate local physical properties of the underground, such as intrinsic and scattering attenuation (Abubakirov & Gusev 1990;Lacombe et al 2003).…”

Section: Introductionmentioning

confidence: 99%

Seismic scattering and absorption parameters in the W-Bohemia/Vogtland region from elastic and acoustic radiative transfer theory

Gaebler¹,

Eulenfeld²,

Wegler³

2015

Geophys. J. Int.

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In this study, frequency-dependent seismic scattering and intrinsic attenuation parameters for the crustal structure beneath the W-Bohemia/Vogtland swarm earthquake region close to the border of Czech Republic and Germany are estimated. Synthetic seismogram envelopes are modelled using elastic and acoustic radiative transfer theory. Scattering and absorption parameters are determined by fitting these synthetic envelopes to observed seismogram envelopes from 14 shallow local events from the October 2008 W-Bohemia/Vogtland earthquake swarm. The two different simulation approaches yield similar results for the estimated crustal parameters and show a comparable frequency dependence of both transport mean free path and intrinsic absorption path length. Both methods suggest that intrinsic attenuation is dominant over scattering attenuation in the W-Bohemia/Vogtland region for the investigated epicentral distance range and frequency bands from 3 to 24 Hz. Elastic simulations of seismogram envelopes suggest that forward scattering is required to explain the data, however, the degree of forward scattering is not resolvable. Errors in the parameter estimation are smaller in the elastic case compared to results from the acoustic simulations. The frequency decay of the transport mean free path suggests a random medium described by a nearly exponential autocorrelation function. The fluctuation strength and correlation length of the random medium cannot be estimated independently, but only a combination of the parameters related to the transport mean free path of the medium can be computed. Furthermore, our elastic simulations show, that using our numerical method, it is not possible to resolve the value of the mean free path of the random medium.

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Section: Introductionmentioning

confidence: 99%

Seismic scattering and absorption parameters in the W-Bohemia/Vogtland region from elastic and acoustic radiative transfer theory

Gaebler¹,

Eulenfeld²,

Wegler³

2015

Geophys. J. Int.

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“…Remarkably similar, diffusion behavior of multiple-scattered electronic wave functions at low temperatures [1,2,3], coherent electromagnetic [4] (optical [5] and microwave [7]), acoustic [8], and elastic [9] waves has permitted impressive advances of the field [6]. Recently, multiple-scattered seismic waves in the Earth crust have been demonstrated to behave in a similar way [10,11]. In the context of these studies, the main quantities of interest are the transport coefficients of disordered samples, such as, e.g., the transmission coefficient T or the conductance g. The average values, fluctuations, full probability distributions, angular, spatial, and temporal correlation functions of T and g have been studied both theoretically and experimentally (see, e.g., Ref.…”

Section: Introductionmentioning

confidence: 99%

Information transfer through disordered media by diffuse waves

Skipetrov

2003

Phys. Rev. E

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We consider the information content h of a scalar multiple-scattered, diffuse wave field psi(r) and the information capacity C of a communication channel that employs diffuse waves to transfer the information through a disordered medium. Both h and C are shown to be directly related to the mesoscopic correlations between the values of psi(r) at different positions r in space, arising due to the coherent nature of the wave. For the particular case of a communication channel between two identical linear arrays of n>>1 equally spaced transmitters or receivers (receiver spacing a), we show that the average capacity proportional, variant n and obtain explicit analytic expressions for /n in the limit of n--> infinity and kl--> infinity, where k=2pi/lambda, lambda is the wavelength, and l is the mean free path. Modification of the above results in the case of finite but large n and kl is discussed as well. If the signal to noise ratio S/N exceeds some critical value (S/N)(c), /n is a nonmonotonic function of a, exhibiting maxima at ka=mpi (m=1,2, em leader ). For smaller S/N, ka=mpi correspond to local minima, while the absolute maximum of /n is reached at some ka approximately (S/N)(1/2)(max) as maximized over the receiver spacing a and the optimal normalized receiver spacing (ka)(opt) as the spacing maximizing . Both (max)/n and (ka)(opt) scale as (S/N)(1/2) for S/N<(S/N)(c), while (ka)(opt)=mpi and (max)/n approximately log(S/N) for S/N>(S/N)(c).

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“…The energy decay of the seismic coda with time depends on the investigated frequency band and is a local property of the subsurface. Parameters such as source mechanism, epicentral distance, magnitude, event depth or source orientation show minor influence on the energy decay in the seismic coda (Trégourès et al 2002). Therefore many studies relate physical properties of the subsurface to the observed local or regional seismic coda signals (Aki 1969;Abubakirov & Gusev 1990;Calvet & Margerin 2013).…”

Section: Scattered Energy In the Seismic Codamentioning

confidence: 99%

The influence of crustal scattering on translational and rotational motions in regional and teleseismic coda waves

Gaebler

Sens‐Schönfelder²,

Korn

2015

Geophysical Journal International

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S U M M A R YMonte Carlo solutions to the radiative transfer equations are used to model translational and rotational motion seismogram envelopes in random elastic media with deterministic background structure assuming multiple anisotropic scattering. Observation and modelling of the three additional components of rotational motions can provide independent information about wave propagation in the Earth's structure. Rotational motions around the vertical axis observed in the P-wave coda are of particular interest as they can only be excited by horizontally polarized shear waves and therefore indicate the conversion from P to SH energy by multiple scattering at 3-D heterogeneities. To investigate crustal scattering and attenuation parameters in south-east Germany beneath the Gräfenberg array multicomponent seismogram envelopes of rotational and translational motions are synthesized and compared to seismic data from regional swarm-earthquakes and of deep teleseismic events. In the regional case a nonlinear genetic inversion is used to estimate scattering and attenuation parameters at high frequencies (4-8 Hz). Our preferred model of crustal heterogeneity consists of a medium with random velocity and density fluctuations described by an exponential autocorrelation function with a correlation length of a few hundred metres and fluctuations in the range of 3 per cent. The quality factor for elastic S-waves attenuation Q S i is around 700. In a second, step simulations of teleseismic P-wave arrivals using this estimated set of scattering and attenuation parameters are compared to observed seismogram envelopes from deep events. Simulations of teleseismic events with the parameters found from the regional inversion show good agreement with the measured seismogram envelopes. This includes ringlaser observations of vertical rotations in the teleseismic P-wave coda that naturally result from the proposed model of wave scattering. The model also predicts, that the elastic energy recorded in the teleseismic P coda is not equipartitioned, unlike the coda of regional events, but contains an excess of shear energy. The results confirm that scattering generating the teleseismic P-wave coda mainly occurs in the crustal part of the lithosphere beneath the receiver. Our observations do not require scattering of high frequency waves in the mantle, but weak scattering in the lithospheric mantle cannot be ruled out.

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Multiple scattering of seismic waves

Cited by 9 publications

References 24 publications

Seismic scattering and absorption parameters in the W-Bohemia/Vogtland region from elastic and acoustic radiative transfer theory

Seismic scattering and absorption parameters in the W-Bohemia/Vogtland region from elastic and acoustic radiative transfer theory

Information transfer through disordered media by diffuse waves

The influence of crustal scattering on translational and rotational motions in regional and teleseismic coda waves

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