Two different graben sets were developed in western Anatolia (Turkey) under the influence of Neogene extension. NE–SW orientated grabens formed during the Miocene and provided suitable environments for the deposition of lacustrine bituminous shales and fan delta sediments. Younger E–W orientated grabens formed during the Pliocene and locally intersected the older NE–SW grabens. Such intersecting graben areas are characterized by superimposed graben fills. The Alaşehir Graben is an example of such a configuration within the E–W orientated Gediz Graben. The hydrocarbon potential and superimposed configuration of the Alaşehir Graben were examined using seismic, gravity and magnetic data. Seismic data were interpreted in an interactive interpretation system, using additional physical parameters generated by calculating instantaneous attributes on time-migrated seismic sections, aiding determinations of lithology and seismic facies. The Alaşehir Graben contains four sedimentary units developed under an extensional tectonic regime and is a superimposed graben containing possible traps as well as a high potential for hydrocarbon generation.