Abstract
We study the frequency- and time-domain techniques which have been used to measure shear attenuation in the mantle using long-period body waveforms. In the time-domain technique, waveform modeling is carried out and the attenuation model that best fits the data is chosen. In the frequency-domain technique, we solve for the attenuation model that best fits the spectra of the seismic waveforms. Though theoretically both these techniques are equivalent, modeling assumptions and measurement biases associated with each technique can give rise to different results. In this study, we compare these two techniques in terms of their accuracy in obtaining mantle shear attenuation. Specifically, we estimate the biases in constraining attenuation from differential SS — S and absolute S waveforms. We carry out these tests using realistic synthetic seismograms and we follow this with an analysis of recorded data to verify the results from the synthetic tests. For the SS — S waveforms, the primary biasing factors are interference with seismic phases due to mantle discontinuities and due to crustal reverberation under the SS bounce point. These factors can affect the t* measurements by up to 0.5 s in the frequency domain and more than 1.5 s in the time domain. For the S waveforms, the frequency-domain measurements are accurate to 0.3 s while the time-domain measurements can vary by more than 2.0 s from the predicted values. These errors are also manifested in the t* measurements made using teleseismically recorded waveforms and lead to comparatively larger noise levels in the time-domain measurements. Based on these results, we propose that in long-period body-wave attenuation studies, frequency-domain techniques should be the method of choice.
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References
Bhattacharyya, J., Shearer, P. M., and Masters, G. (1993), Inner Core Attenuation from Short-period PKP (BC) versus PKP (DF) Waveforms, Geophys. J. Int. 114, 1–11.
Bhattacharyya, J., Masters, G., and Shearer, P. M. (1996), Global Lateral Variations of Shear-wave Attenuation in the Upper Mantle, J. Geophys. Res. 101, 22,273–22,289.
Bhattacharyya, J., Masters, G., and Romanowicz, B. (1998), Global Lateral Variations of Shear-wave Attenuation in the Mantle, Geophys. J. Int., in review.
Chan, W. W., and Der, Z. A. (1988), Attenuation of Multiple ScS in Various Parts of the World, Geophys. J. Int. 92, 303–314.
Choy, G. L., and Richards, P. G. (1975), Pulse Distortion and Hilbert Transformation in Multiply Reflected and Refracted Body Waves, Bull. Seismol. Soc. Am. 65, 55–70.
Ding, X.-Y., and Grand, S. P. (1993), Upper Mantle Q Structure under the East Pacific Rise, J. Geophys. Res. 98, 1973–1985.
Dziewonski, A. M., Hale, A. L., and Lapwood, E. R. (1974), Parametrically Simple Earth Models Consistent with Geophysical Data, Phys. Earth Planet. Inter. 10, 12–48.
Dziewonski, A. M., and Anderson, D. L. (1981), Preliminary Reference Earth Model, Phys. Earth Planet. Inter. 25, 297–356.
Flanagan, M. P., and Wiens, D. A. (1990), Attenuation Structure beneath the Lau Backarc Spreading Center from Teleseismic S Phases, Geophys. Res. Lett. 17, 2117–2120.
Flanagan, M. P., and Wiens, D. A. (1994), Radial Upper Mantle Structure of Inactive Backarc Basins from Differential Shear Wave Measurements, J. Geophys. Res. 99, 15,469–15,485.
Gilbert, F., and Dziewonski, A. M. (1975), An Application of Normal Mode Theory to the Retrieval of Structural Parameters and Source Mechanisms from Seismic Spectra, Phil. Trans. Roy. Soc. London, Ser. A 278, 187–269.
Liu, H., Anderson, D. L., and Kanamori, H. (1976), Velocity Dispersion due to Anelasticity: Implications for Seismology and Mantle Composition, Geophys. J. R. Astron. Soc. 47, 41–58.
Lay, T., and Wallace, T. C. (1983), Multiple ScS Travel Times and Attenuation beneath Mexico and Central America, Geophys. Res. Lett. 10, 301–304.
Lay, T., and Wallace, T. C. (1988), Multiple ScS Attenuation and Travel Times beneath Western North America, Bull. Seismol. Soc. Am. 78, 2041–2061.
Lundquist, G. M., and Cormier, V. C. (1980), Constraints on the Absorption Band Model of Q, J. Geophys. Res. 85, 5244–5256.
Mooney, W. D., Laske, G., and Masters, T. G. (1998), CRUST 5.1: A Global Crustal Model at 5° × 5°, J. Geophys. Res. 103, 727–747.
Reid, F., and Woodhouse, J. H. (1994), Measurement of Differential Travel Times and t* and the Structure of the Upper Mantle, EOS, Trans. AGU 78, F485.
Revenaugh, J. S., and Jordan, T. H. (1991), Mantle Layering from ScS Reverberations, 1. Waveform Inversion of Zeroth-order Reverberations, J. Geophys. Res. 96 19,749–19,762.
Sheehan, A. F., and Solomon, S. C. (1992), Differential Shear-wave Attenuation and its Lateral Variation in the North Atlantic Region, J. Geophys. Res. 97, 15,339–15,350.
Sipkin, S. A., and Jordan, T. H. (1980), Regional Variations of Q Scs , Bull. Seismol. Soc. Am. 70, 1071–1102.
Sipkin, S. A., and Revenaugh, J. S. (1994), Regional Variation of Attenuation and Travel Time in China from Analysis of Multiple-ScS Phases, J. Geophys. Res. 99, 2687–2699.
Thomson, D. J. (1982), Spectrum Estimation and Harmonic Analysis, IEEE Proc. 70, 1055–1096.
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Bhattacharyya, J. (1998). Comparison between Time-domain and Frequency-domain Measurement Techniques for Mantle Shear-wave Attenuation. In: Mitchell, B.J., Romanowicz, B. (eds) Q of the Earth: Global, Regional, and Laboratory Studies. Pageoph Topical Volumes. Birkhäuser, Basel. https://doi.org/10.1007/978-3-0348-8711-3_8
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DOI: https://doi.org/10.1007/978-3-0348-8711-3_8
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