Attenuation of coda waves in Western Anatolia

Abstract

By analyzing the decay of coda wave amplitude, we have determined coda Q, Q c, in Western Anatolia (Turkey). Using the single isotropic scattering model, we analyzed 116 earthquakes which registered at the Gebze station by using five narrow frequency bands centered at 1.5, 3, 6, 8 and 10 Hz. Coda Q values were obtained using different lapse times, between 30 and 190 s, in steps of 10 s. Coda Q c for Western Anatolia depends on frequency and lapse time. For a lapse time of 30 s, the frequency dependence of Q c is Q c (ƒ) = 50.7ƒ 1.01 and for a lapse time of 190 s it is Q c (ƒ) = 183.2ƒ 0.76 . In this region, the exponential value of the Q c frequency dependence is practically constant, between 0.7 and 1.0. The obtained coda Q c values were compared with those estimated in other regions. The coda Q c values for lapse times between 60 and 100 s for Western Anatolia and Southern Spain are practically the same, indicating similar coda wave attenuation patterns in both regions of the Mediterranean Basin.