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

Abstract

<p align="left">The attenuation properties of Delhi &amp; surrounding region have been investigated using 6<em>2</em> local earthquakes recorded at nine stations. The frequency dependent quality factors <em>Q</em><em>_a</em> (using P-waves) and <em>Q</em><em>_b</em> (using S-waves) have been determined using the coda normalization method. Quality factor of coda-waves (<em>Q_c</em>) 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 <em>Q_i</em> (intrinsic attenuation parameter) and <em>Q_s</em> (scattering attenuation parameter) for the region. The values <em>Q</em><em>_a, Q</em><em>_b,Q_c,Q_i and Q_s</em> estimated are frequency dependent in the range of 1.5Hz-9Hz. Frequency dependent relations are estimated as <em>Q</em><em>_a=52f^1.03, Q</em><em>_b=98f^1.07 and Q_c=158f^0.97</em>. <em>Q_c</em> estimates lie in between the values of <em>Q_i</em> and <em>Q_s</em> but closer to <em>Q_i</em> at all central frequencies. Comparison between <em>Q_i </em>and <em>Q_s</em> shows that intrinsic absorption is predominant over scattering for Delhi and surrounding region. </p>