Estimation of Coda-Q for Mainland Gujarat region of Western Deccan Volcanic Province, India
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In the present study, we have estimated the quality factor Coda-Q (Q$_c$) using the single backscattering model for Mainland Gujarat region of Western Deccan Volcanic Province (DVP) India. The said region comes under seismic zone III as per seismic zonation map of India and is vulnerable for earthquakes of magnitude up to 6.0. Mainland Gujarat comprises of the eastern rocky highlands and western alluvial plains. The broadband waveforms of 80 local earthquakes (Mw 2.5–4.3) having depths in the range (2.0–34.0 km) recorded at eight stations of Mainland Gujarat have been used for the analysis. The average values of Q$_c$ for the lapse time windows of 20–90 s with standard error varies respectively from 113 ± 12 to 411 ± 37 at 2 Hz and 1008 ± 150 to 3600 ± 400 at 16 Hz, respectively. This suggests that the region is more attenuative and heterogeneous than the Kachchh and Saurashtra of DVP. The increase in ‘Q$_c$’ values with lapse time displays the depth dependence of ‘Q$_c$’ because of the fact that longer lapse time windows will sample larger area. We have compared the frequency-dependent relations for ‘Q$_c$’ derived here with those of other parts of India and the World. The study is inevitable for the estimation of source parameters, thereby, evaluation of seismic hazard of the region.
ARPAN SHASTRI1 2 SANTOSH KUMAR1
Volume 132, 2023
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