Body wave attenuation characteristics in the crust of Alborz region and North Central Iran

Farrokhi, Mohsen; Hamzehloo, H.

doi:10.1007/s10950-016-9624-2

Cited by 13 publications

(3 citation statements)

References 55 publications

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“…These values are in agreement with the values reported for active seismotectonic regions (e.g. Mahood 2014;Farrokhi & Hamzehloo 2017;Amiri Fard et al 2019). The computed Q 0 value for Pn waves is also 306.8 and the frequency parameter is 0.51.…”

Section: R E S U Lt a N D Discussionsupporting

confidence: 90%

Local and regional P-wave spectral attenuation model for Iran

Bajestani

Ansari

Karkooti

2020

Geophysical Journal International

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Summary A robust frequency-dependent local and regional P wave attenuation model is estimated for continental paths in the Iranian Plateau. In order to calculate the average attenuation parameters, 46337 vertical-component waveforms related to 9267 earthquakes, which are recorded at the Iranian Seismological Center (IRSC) stations, have been selected in the distance range 10 to 1000 km. The majority of the event's magnitudes are less than 4.5. This collection of records provides high spatial ray path coverage. Results indicate that the shape of attenuation P wave curve versus distance is not uniform and has three distinct sections with hinges at 90 and 175 km. A tri-linear model for attenuation of P wave amplitude in the frequency range 1–10 Hz is proposed in this study. Fourier spectral amplitudes are found to decay as R−1.2 (where R is hypocentral distance), corresponding to geometric spreading within 90 km from the source. There is a section from 90 to 175 km, where the attenuation is described as R0.8, and the attenuation is described well beyond 175 km by R−1.3. Moreover, the average quality factor for Pg and Pn waves (QPg and QPn), related to anelastic attenuation is obtained as Qpg = (54.2 ± 2.6)f(1.0096±0.07) and Qpn = (306.8 ± 7.4)f (0.51±0.05). There is a good agreement between the results of the model and observations. Also, the attenuation model shows compatibility with the recent regional studies. From the results it turns out that the amplitude of P waves attenuates more rapidly in comparison with the global models in local distances.

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Section: R E S U Lt a N D Discussionsupporting

confidence: 90%

Local and regional P-wave spectral attenuation model for Iran

Bajestani

Ansari

Karkooti

2020

Geophysical Journal International

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“…Hassani et al (2011) estimated the S-wave quality factor as Q S (f)=151f 0.75 using GIT with a dataset consisting of 40 earthquakes recorded in East-Central Iran for the frequency range 0.4-15 Hz. Farrokhi and Hamzehloo (2016) investigated the attenuation of P and S waves in Alborz and north central part of Iran. They applied the extended coda normalization method (CNM) for 380 local earthquakes in the seven frequency bands between 0.4 to 24 Hz to define Q S (f)=83 f 0.99 and Q S (f)= 68f 0.96 in Alborz region and North Central Iran, respectively.…”

Section: Discussionmentioning

confidence: 99%

Attenuation characteristics, source parameters and site effects from inversion of S waves of the March 31, 2006 Silakhor aftershocks

Ahmadzadeh

Parolai

Doloei

et al. 2017

Annals of Geophysics

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“…Rahimi et al (2010) and Farrokhi et al (2015) estimated coda-wave attenuation in the central and eastern Alborz. Farrokhi and Hamzehloo (2016) investigated body wave attenuation…”

Section: Introductionmentioning

confidence: 99%

Estimation of Quality Factor (Qβ) Using Accelerograms of Ahar-Varzaghan Earthquakes, Northwestern Iran

Mahood

Amiri

2017

IJGE

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High-frequency strong-motion data of two recent major earthquakes in the Ahar-Varzaghan region, Northwestern Iran, have been used to determine shear-wave quality factor (Qβ (f )) and seismic source parameters. Data from a local array of 12 stations, two main shocks (Ahar-Varzaghan doublet earthquakes (Mw 6.4 and 6.3) on August 11, 2012), and 38 aftershocks of magnitude 4.1 -5 were analyzed. The classic Brune model is used to predict the shape of the source spectrum and to provide scaling relationships between spectral and source parameters. In order to obtain reliable estimates of the source spectrum, the effects of attenuation need to be estimated and corrected. By using an inversion algorithm in this work, an average relation in the form Qβ = (114 ± 21) f (0.90 ± 0.07) is obtained. The best fit theoretical spectrum provides final values of source parameters, i.e. seismic moment Mo and corner frequency fc as 3.19 × 10 25 dyne cm and 0.69 Hz, respectively, for the first event. Obtained Q(f) relationship suggests a low Qo value (< 200) and a high n value (> 0.8) for high heterogeneous, tectonically and seismically active regions.

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Body wave attenuation characteristics in the crust of Alborz region and North Central Iran

Cited by 13 publications

References 55 publications

Local and regional P-wave spectral attenuation model for Iran

Local and regional P-wave spectral attenuation model for Iran

Attenuation characteristics, source parameters and site effects from inversion of S waves of the March 31, 2006 Silakhor aftershocks

Estimation of Quality Factor (Qβ) Using Accelerograms of Ahar-Varzaghan Earthquakes, Northwestern Iran

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