Azimuthal Path Variations of Regional Body Wave Attenuation via Coda-Source Normalized Method: An Example from Eastern Marmara (NW Turkey).

This study examines the body wave attenuation characteristics for the eastern section of the Marmara Region (NW Turkey). Qp and Qs values were obtained using the vertical and two horizontal components of the three-component broad-band data, respectively that recorded in a circular areal extent with 120 km radius centred at the ARMT station on the Armutlu Peninsula. The database was prepared according to back-azimuthal distributions, and data-packs representing 36 different back-azimuthal slices were subjected to the Extended-Coda-Normalization-Method to examine the azimuthal path-dependence of the attenuation characteristics of direct body waves in the region. While the region corresponding to the basins in the Marmara Sea with relatively low seismicity is represented by high Q values, low Q values were observed in areas with intense faulting and seismicity in the NE of the study area. Additionally, direction-independent attenuation functions for the region were calculated as Qp = 18 ± 1f0.92±0.2 and Qs = 38 ± 1f0.87±0.01 for P and S phases, respectively. [ABSTRACT FROM AUTHOR]