Attenuation of high frequency<i>P</i>and<i>S</i>waves in the crust of the East-Central Iran

Mahood, Majid; Hamzehloo, H.; Doloei, Gholam Javan

doi:10.1111/j.1365-246x.2009.04363.x

Cited by 55 publications

(13 citation statements)

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“…2007); NE Sonora, Mexico (Castro et al . 2008); east central Iran (Ma’hood et al . 2009); Cairo, Egypt (Abdel‐Fattah 2009) and Garhwal Himalaya (Padhy 2009 a ).…”

Section: Resultsmentioning

confidence: 99%

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Frequency-dependent attenuation of P and S waves in northeast India

Padhy¹,

Subhadra²

2010

Geophysical Journal International

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S U M M A R YWe have analysed 202 seismograms recorded at 10 seismic stations in the northeast (NE) India region to infer the frequency-dependent attenuation characteristics of both P and S waves, in the frequency range from 1.5 to 24 Hz and in the distance range from 30 to 100 km. We used extended coda-normalization method to determine the attenuation of P wave (Q −1 P ) and S wave (Q −1 S ). The results show that both P and S waves undergo a strong attenuation along ray paths. The values of Q −1 P and Q −1 S , corresponding to spectral amplitude decays, show strong frequency dependence and are expressed as Q −1 P = (0.035 ± 0.014) f −(0.96±0.01) and Q −1 S = (0.014 ± 0.006) f −(0.94±0.03) , respectively, in 1.5-24 Hz. The ratio Q −1 P /Q −1 S is found to be larger than unity for the whole frequency range. The high frequency dependence of both P-and S waves indicate the highest attenuation among the world at lower frequencies.

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“…2007); NE Sonora, Mexico (Castro et al . 2008); east central Iran (Ma’hood et al . 2009); Cairo, Egypt (Abdel‐Fattah 2009) and Garhwal Himalaya (Padhy 2009 a ).…”

Section: Resultsmentioning

confidence: 99%

“…2006 for Q −1 S ), Koyna, India (Sharma et al . 2007), Bhuj, India (Padhy 2009b), Cairo, Egypt (Abdel‐Fattah 2009) and east‐central Iran (Ma’hood et al . 2009).…”

Section: Introductionmentioning

confidence: 99%

Frequency-dependent attenuation of P and S waves in northeast India

Padhy¹,

Subhadra²

2010

Geophysical Journal International

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“…To invert phase and group velocity dispersions, we used the average Q S structural models to avoid anelastic dispersion effect. The average values of Q S are taken from the literature as ∼25 and ∼55 for crust and upper mantle (Cong and Mitchell, 1998;Motazedian, 2006;Rahimi and Hamzehloo, 2008;Ma'hood et al, 2009;Rahimi et al, 2009Rahimi et al, , 2010.…”

Section: Constructing the Starting Modelmentioning

confidence: 99%

Shear-Wave Velocity Tomography of the Lithosphere-Asthenosphere System beneath the Iranian Plateau

Rahimi¹,

Hamzehloo²,

Vaccari³

et al. 2014

Bulletin of the Seismological Society of America

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We conducted a tomographic inversion of Rayleigh-wave dispersion to obtain 2D phase and group velocity tomographic images in the 10-100 s period range and shear-wave velocity structures for the Iranian plateau. For this purpose, the fundamental mode of Rayleigh waves, recorded along 1586 paths by 29 broadband stations, was identified by applying the frequency time analysis (FTAN) to each epicenter-station path which simultaneously satisfies the two-station method conditions. The fundamental modes identified by FTAN have been used to determine the path-average interstation phase and group velocities at selected periods. With this procedure, 243 group and phase velocity dispersion curves were processed to obtain tomographic maps by applying the Yanovskaya-Ditmar formulation for periods in the 10-100 s range. Averaged dispersion curves of phase and group velocities, which represent six rather homogeneous regions, are computed. Finally, we used a fully nonlinear inversion procedure to derive tomographic images of the elastic structure of the lithosphere and asthenosphere of the six main structural and seismotectonic features of the Iranian plateau. The dense path coverage in the Iranian plateau permits us to produce images that have substantially higher lateral resolution compared to images currently available from global and regional group velocity studies. Tomographic maps at high frequencies are well correlated with the upper crust structure, especially with sediment layers thickness. Estimated shear-wave velocity structures are well correlated with the shield-like lithosphere structure in Zagros. A low-velocity zone (LVZ) is not detected in Alborz or the south Caspian basin, which can imply thrusting of the oceanic crust of the southern Caspian Sea under the Alborz to the south. LVZs are derived for the region east of Iran, central Iran, and Kopeh Dagh.

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“…We note that the simulations are performed for rock conditions in both host and target regions in order to avoid the local site effects which might not be accurately obtained or incorporated. Table 4 displays the seismological parameters used in scenario events for Iran and Turkey which are adopted from Ma'hood et al (2009), Ugurhan and Askan (2010), and Askan et al (2013). We note that the seismological parameters in host regions adopted from these references Generic rock conditions Generic rock conditions were validated robustly against observations in simulations of several past earthquakes.…”

Section: Hybrid-empirical Ground Motion Analyses For Georgiamentioning

confidence: 99%

Hybrid-Empirical Ground Motion Estimations for Georgia

2016

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Ground motion prediction equations are essential for several purposes ranging from seismic design and analysis to probabilistic seismic hazard assessment. In seismically active regions without sufficiently strong ground motion data to build empirical models, hybrid models become vital. Georgia does not have sufficiently strong ground motion data to build empirical models. In this study, we have applied the host-totarget method in two regions in Georgia with different source mechanisms. According to the tectonic regime of the target areas, two different regions are chosen as host regions. One of them is in Turkey with the dominant strike-slip source mechanism, while the other is in Iran with the prevalence of reverse-mechanism events. We performed stochastic finite-fault simulations in both host and target areas and employed the hybrid-empirical method as introduced in Campbell (2003). An initial set of hybrid empirical ground motion estimates is obtained for PGA and SA at selected periods for Georgia.

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Attenuation of high frequencyPandSwaves in the crust of the East-Central Iran

Cited by 55 publications

References 41 publications

Frequency-dependent attenuation of P and S waves in northeast India

Frequency-dependent attenuation of P and S waves in northeast India

Shear-Wave Velocity Tomography of the Lithosphere-Asthenosphere System beneath the Iranian Plateau

Hybrid-Empirical Ground Motion Estimations for Georgia

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