Frequency dependent attenuation of seismic waves for Delhi and surrounding area, India

Babita Sharma, Prasantha Chingtham, Anup K. Sutar, Sumer Chopra, Haldhar P. Shukla


The attenuation properties of Delhi & surrounding region have been investigated using 62 local earthquakes recorded at nine stations. The frequency dependent quality factors Qa (using P-waves) and Qb (using S-waves) have been determined using the coda normalization method. Quality factor of coda-waves (Qc) has been estimated using the single backscattering model in the frequency range from 1.5 Hz to 9 Hz. Wennerberg formulation has been used to estimate Qi (intrinsic attenuation parameter) and Qs (scattering attenuation parameter) for the region. The values Qa, Qb, Qc, Qi and Qs estimated are frequency dependent in the range of 1.5Hz-9Hz. Frequency dependent relations are estimated as Qa=52f1.03, Qb=98f1.07 and Qc=158f0.97. Qc estimates lie in between the values of Qi and Qs but closer to Qi at all central frequencies. Comparison between Qi and Qs shows that intrinsic absorption is predominant over scattering for Delhi and surrounding region. 


Coda; Intrinsic; Scattering; Attenuation; Frequency

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Published by INGV, Istituto Nazionale di Geofisica e Vulcanologia - ISSN: 2037-416X