Attenuation of High frequency P and S Waves in Qeshm Island, Iran
Seismic waves attenuation of direct shear and P waves was investigated for the crust in Qeshm Island, the greatest Iranian Island in the Persian Gulf in north-western flank of the strait of Hormoz, using 100 seismograms of local earthquakes recorded after 2005 Qeshm earthquake. The data of a seismological network consisting of 17 stations,installed after the earthquake. We applied the single-station method (extended coda normalization method) to analyze Qp-1 and Qs-1 using the ratio of the P and S-wave to Coda-wave amplitude spectra, in the frequency range of 1.5 36 Hz, as a function of distance. The Qp and Qs is analyzed by using 66 lapse times of 22.5 87.5 seconds for center frequencies 1.5, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 14, 16, 18, 20, 24, 28, 32 and 36 Hz. The values of Qp-1 and Qs -1 estimated shows frequency dependence and decrease with increase of lapse time and distance indicates that the Q value increases with depth. The inverse of average of all quality factors for each frequency band is measured as Qp-1 and Qs-1. The estimated Qp-1 and Qs-1 is highly frequency dependant and decrease from 0.07 and 0.06 in 1.5 Hz to 0.003 and 0.006 in 36 Hz, Respectively. Estimated Qp-1 and Qs -1 shows high frequency dependence with functional form 97 . 0 0.06 f and 83 . 0 0.1 f , respectively. The relatively low value of Q obtained in this study agrees with the value which is expected for a seismically active region such as Qeshm.
attenuation coda normalization Qeshm Island
A.Zarean M.Farrokhi S.Chaychizadeh
Geophysists,Department of Geophysics,TOZco,Geological Survey of Iran,Tehran,Iran PhD.Student,Department of Seismology,International Institute of Earthquake Engineering andSeismology Ms.Student,Geophysics Institute,Tehran University,Tehran,Iran
国际会议
14th World Conference on Earthquake Engineering(第十四届国际地震工程会议)
北京
英文
2008-10-12（万方平台首次上网日期，不代表论文的发表时间）