Scattering model to explain seismic Q observations in the lithosphere between 1 and 20 Hz

Journal Article · Sun Nov 01 04:00:00 EST 1981 · Geophys. Res. Lett.; (United States)

DOI:https://doi.org/10.1029/GL008i011p01126· OSTI ID:5673301

Dainty, A M

Observations of lithospheric Q for shear waves in the range 1--30 Hz reported in the literature are examined using a scattering model consisting of randomly distributed spheres. For the single scattering approximation I have assumed 1/Q = 1/Q/sub i/+gv/..omega.., where Q/sub i/ is the intrinsic Q due to anelasticity, v is the velocity of shear waves, ..omega.. is angular frequency and g is the turbidity. g is taken as a constant in this paper, since g = ..integral.. n(a)sigmada, where n(a)da is the number of scattering spheres of radius a/unit volume and sigma is the scattering cross-section for a sphere, this suggests that geometrical scattering dominates. This will be true for ka>1, where k is wavenumber. Based on this criterion and the observation that Q is large (i.e. g small) at a frequency of 0.05 Hz, a is of the order of magnitude 1--10 km. Fits of observations of shear wave Q from Japan and Central Asia indicate that Q/sub i/ = 2000 +- 500 for the lithosphere of both regions; g = 0.01 km for the Japan observations and g = 0.005 km/sup -1/ for Central Asia.

• Research Organization: School of Geophysical Sciences, Georgia Institute of Technology, Atlanta, Georgia 30332
• OSTI ID: 5673301
• Journal Information: Geophys. Res. Lett.; (United States), Journal Name: Geophys. Res. Lett.; (United States) Vol. 8:11; ISSN GPRLA
• Country of Publication: United States
• Language: English

Related Subjects

58 GEOSCIENCES
580201* -- Geophysics-- Seismology & Tectonics-- (1980-1989)
ANGULAR VELOCITY
ATTENUATION
EARTH CRUST
FREQUENCY DEPENDENCE
SEISMIC WAVES
TURBIDITY
VELOCITY
WAVE PROPAGATION