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Abstract: The attenuation of P and S waves caused by quarry blasts in south and southeast Tehran was estimated using the extended coda-normalization method. The analysis used 230 seismic events from quarry blasts recorded in a range of 3–50km using a network of 13 seismic stations. To estimate the frequency-dependent Q-value, the seismograms were band-pass filtered at the central frequencies (f i ) of 1, 1.5, 2, 2.5, 3, 3.5, 4, 5, 6, 7, 8, 10 and 12Hz using a phaseless eight-pole Butterworth band pass filter with a bandwidth of f i /√2 to f i √2. We showed that geometrical spreading exponent value (γ) is a variable depending on the propagation distance. The attenuation parameters were: Q p −1=(100±6) ×10 −3 (f −1±0.07) and Q s −1=(73±2)×10 −3 (f −1.06±0.03) indicating that the strong frequency dependency of Q p −1 and Q s −1 can propose heterogeneity of the medium. The ratio of Q p −1 /Q s −1 obtained in this study is larger than unity and less than 2 for the entire frequency range. Also, Q s ≥Q p indicates that the region is composed of half-saturated rocks. [Copyright &y& Elsevier]