Interplay between the dynamic effects of the northward subduction of the African plate beneath the Aegean continental fragment and the North Anatolian dextral strike slip fault to the north caused a complex large-scale extensional crustal deformational domain, named Aegean extensional province.
The Gediz-Alaşehir Graben (GAG), being in that large scale extensional terrain, is a NW-SE trending extensional basin developed to the north of K. Menderes Graben (KMG). NW-SE trending Manisa fault is one of the important elements of the GAG, displaying active fault geomorphology.
The slip data were collected from the high angle normal faults, Manisa fault, controlling the Quaternary conﬁguration and faults that are cutting through the Miocene sequences. Angelier’s reverse inversion method (WinTensor) was carried out to differentiate the deformational phases acting on the Manisa fault, based on σ1 - σ3 relation and θ ratio.
The Manisa fault is a high angle normal and dipping towards NE where the final dip-slip motion overprinted onto strike-slip motion. The analysis of the fault slip data simply implies an almost NNW-SSE and NE-SW, two extensional periods acted in the region possibly following Early Miocene contractional period since post-Oligocene. The Plio-Quaternary NNW-SSE extension overprinted onto almost ENE-WSW compression (dextral strike-slip data) which is finally overprinted by the NE-SW to NW-SE multi-directional extension in Aegean region.
To sum up; final phase of the intermittent extensional deformation, NE-SW to NW-SE multi-directional extension, superimposed on the older contractional systems, evolved under the control of North Anatolian strike-slip shear in north and southern Aegean subduction in the south with a cumulative regionwide 30° counterclockwise rotation of western Anatolia since latest Miocene or the contractional data might be possibly inherited from a strike slip structure at depth (“İzmir-Balıkesir transfer zone or Tear”) or else might be evolved along the edges of block boundaries of rotated fault domains.
Key words: Aegean extensional province, Manisa fault, normal faulting, strike-slip faulting.