Frankel, Arthur and Clayton, Robert W.
A finite-difference simulation of wave propagation in two-dimensional random media.
Bulletin of the Seismological Society of America, 74
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A finite-difference algorithm is used to generate synthetic seismograms for waves propagating through two-dimensional random media. The media have a significant component of their material properties varying randomly over length scales smaller than the seismic wavelength and are meant to approximate the heterogeneity of the crust and upper mantle. The finite-difference technique retains all multiply scattered and diffracted waves, and also accounts for transmission losses.
The synthetic seismograms clearly exhibit coda and apparent attenuation caused by scattering. For a medium with a white wavenumber spectrum of velocity fluctuations, the coda is higher frequency than the initial pulse. The apparent attenuation is greatest when the scatterer size is comparable to the seismic wavelength. The spectra of the coda generally increase in frequency as the scatterers decrease in size. Examples demonstrate how scattering can produce spectra with broad peaks and sharp fall-offs that can make the determination of the source spectra and corner frequencies of small earthquakes extremely difficult.
|Additional Information:||© 1984 Seismological Society of America.
Manuscript received 17 May 1984.
We thank William Menke and Peter Malin for useful discussions about scattering. The microearthquake
data from the Toktogul network (Figure 15) were analyzed while one of the authors (A.F.) was a
research associate at the Lamont-Doherty Geological Observatory. The research for this paper was
supported by a grant from the Sun Oil Company. A.F. was supported by a postdoctoral Bantrell Fellowship.|
|Funding Agency||Grant Number|
|Sun Oil Co.||UNSPECIFIED|
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|Other Numbering System Name||Other Numbering System ID|
|Caltech Seismological Laboratory||4079|
|Official Citation:||Arthur Frankel and Robert W. Clayton
A finite-difference simulation of wave propagation in two-dimensional random media Bulletin of the Seismological Society of America, December 1984, v. 74, p. 2167-2186|
|Usage Policy:||No commercial reproduction, distribution, display or performance rights in this work are provided.|
|Deposited On:||16 Oct 2012 17:25|
|Last Modified:||31 Jan 2017 21:46|
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