Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Estimation of Attenuation Function for Shear Waves Phase in Lorestan Province by Using Darb-e-Astane Earthquake (2006) Acceleration Data

Document Type : Original Research Paper

Authors
H. Rahimi
H. Hamzeh Lou
International Institute of Earthquake Engineering and Seismology, Tehran, Iran
10.22071/gsj.2009.57380
Abstract
     In general, seismic attenuation is caused by a combination of both scattering and intrinsic mechanisms. Scattering redistributes wave energy within the medium but does not remove energy from the overall wave field. In contrast, intrinsic attenuation mechanisms convert wave energy to heat through friction, viscosity, and thermal relaxation processes. The frequency-domain spectral decay method is employed to estimate frequency dependence value of Qs.
We used foreshock, main-shock and aftershock of Darb-e-Astane earthquake acceleration data with magnitude of 5.1, 6.1 and 4.9 for estimation at 1.5, 3, 6, 12 and 24 Hz central frequencies, respectively. The estimated average frequency dependence shear wave quality factor gives the relation. Shear wave quality factor are increasing from 156 to 592 at frequency band of 1-2 Hz and 16-32 Hz, respectively.
The Q0 value with frequency for this area is similar to those obtained for similar tectonically active regions in the world.
Keywords
Shear wave attenuation
Spectral decay method
Darb-e-Astane earthquake
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Scientific Quarterly Journal of Geosciences
Volume 18, Issue 70
Winter 2009
Pages 94-101