Figure 1. Top: Earlier attenuation studies performed in Turkey. (1) Akinci and Eyidogan (1996); (2) Grosser et al. (1998); (3) Akinci and Eyidogan (2000); (4) Akyol et al. (2002); (5) Kaslilar-Özcan et al. (2002); (6) Gündüz et al. (1998); (7) Akinci et al. (2004); (8) this study. Bottom: the region investigated in the present work and the main alluvial basins (gray regions).