Scientific Quarterly Journal of Geosciences

Scientific Quarterly Journal of Geosciences

Spectral Analysis of Shear Waves Acceleration Recorded in the Qeshm Earthquake (Persian Gulf) 2005 for Estimate Source Parameters and Environment Attenuation

Document Type : Original Research Paper

Authors
Habib Rahimi 1
Nasrollah Kamalian 1
Hosein Hamzeloo 2
1 Institute of Geophysics of Tehran University , Tehran, Iran
2 International Institute of Earthquake Engineering and Seismology, Tehran, Iran
Abstract
The Qeshm earthquake in 27 November 2005 with magnitude ML=5.6; mb=6.2 occurred in Qeshm Island in the Persian Gulf and the main shock recorded in 11 strong motion acceleration building house research center (BHRC).
In the study, the strong motion records are used to obtain an estimate of source parameters, high frequency attenuation and spectral decay parameter for 6 stations from 11 stations that is good S/N rate.
The source parameters are obtained by fitting the data by a dislocation source model combined with an exponential model for the attenuation. The source parameter estimated is as follow:
M0=1.13*1025±5*1024 dyn-cm, r=6.3±1.17 Km, Δu=26±1.4 cm
Δσ=21±1.2 bar, Td=4.3 sec                                
                                                                                                         
And estimated moment magnitude (Mw=5.95±0.17) agree well with values obtained previously from Harvard University by CMT method.
The high frequency attenuation obtained using from amplitude spectral method that can be written as A (f,r)=G(r).e -πrf/Qß  that here G(r)  is geometrical spreading.
Estimates of path averaged crustal shear wave quality factors give results in the range between 60 - 367, and mean of spectral decay parameters for two horizontal components in the ranges between 0.08 - 0.12 sec.
Keywords
source parameters
attenuation
spectral decay parameter
source spectral method
Qeshm
Persian Gulf

Subjects

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Scientific Quarterly Journal of Geosciences
Volume 16, Issue 61
Autumn 2006, Vol. 16, No.61
Autumn 2006
Pages 200-207