frequency dependent attenuation of seismic waves for delhi and surrounding area, india

The attenuation properties of Delhi & surrounding region have been investigated using 62 local earthquakes recorded at nine stations. The frequency dependent quality factors Q_a (using P-waves) and Q_b (using S-waves) have been determined using the coda normalization method. Quality factor of coda-waves (Q_c) 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 Q_i (intrinsic attenuation parameter) and Q_s (scattering attenuation parameter) for the region. The values Q_a, Q_b, Q_c, Q_i and Q_s estimated are frequency dependent in the range of 1.5Hz-9Hz. Frequency dependent relations are estimated as Q_a=52f^1.03, Q_b=98f^1.07 and Q_c=158f^0.97. Q_c estimates lie in between the values of Q_i and Q_s but closer to Q_i at all central frequencies. Comparison between Q_i and Q_s shows that intrinsic absorption is predominant over scattering for Delhi and surrounding region.