Attenuation of S waves in the lithosphere due to scattering by its random velocity structure

Journal Article · Fri Sep 10 04:00:00 EDT 1982 · J. Geophys. Res.; (United States)

DOI:https://doi.org/10.1029/JB087iB09p07779· OSTI ID:5985486

Sato, H

Recent seismological studies suggest that the amplitude attenuation of S waves in the lithosphere may be primarily due to scattering by its random inhomogeneity. There is, however, a disturbing discrepancy between statistical scattering theory and observation with regard to the asymptotic frequency dependence of Q/sup -1/ in the high-frequency limit. Although the observed Q/sup -1/ decreases with frequency above 1 Hz, the usual mean wave formalism predicts Q/sup -1/ of media with random velocity fluctuation increases with frequency; we take a mean over waves with large travel time fluctuations that are caused by long-scale velocity fluctuations compared with the wavelength studied. We propose a new statistical averaging method; mean wave is defined after the correction of travel time fluctuations. The random media with a mean square fractional velocity fluctuation of 5.0 x 10/sup -3/ and a correlation distance of 4.0 km will explain the observed and partially conjectured Q/sup -1/ for frequencies from 0.05 to 30 Hz.

• Research Organization: Department of Earth and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, Massachusetts 02139
• OSTI ID: 5985486
• Journal Information: J. Geophys. Res.; (United States), Journal Name: J. Geophys. Res.; (United States) Vol. 87:B9; ISSN JGREA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
ATTENUATION
FREQUENCY DEPENDENCE
SCATTERING
SEISMIC S WAVES
SEISMIC WAVES