The East Anatolian Fault: Structural pattern and relationship with the Dead Sea Transform

The NE-SW trending left lateral East Anatolian transform fault (EAF), is a major plate boundary, accommodates most of the active deformation between the Arabian and Anatolian plates. It is connected to the Dead Sea transform fault (DSF) at the southwestern continuation. However, relationship between EAF and DSF is still under discussion. In this paper, we present geometry of the EAF in the regional active fault pattern especially in the Kahramanmaras-Adana-Antakya region. The EAF is about 580 km-long between Karliova triple junction and Antakya. It was formed in the late Pliocene and has achieved a maximum offset 15-17 km. GPS data indicate that recent slip rate is about 10 mm/y along the EAF. It is divided into seven main geometric sections. While trend of the fault is almost ENE-WSW between Turkoglu and Karliova, general strike of the fault is N30E along the Turkoglu-Antakya section having approximately similar orientation with northern section of the DSF. Our new data suggest that the EAF divides into two main strands west of Celikhan as the southern and the northern. The Southern strand is the main fault connecting to the DSF. The northern strand bifurcates from the main strand at the west of Celikhan and extends parallel to the Taurus orogenic belt forming a large bend convex to the south between Surgu and Adana basin. Total length of this strand is about 350 km. From east to west, the eastern part of the strand consists of the Surgu, Elbistan and Goksun fault segments, trending E-W. General strike of the strand turns into from E-W to NE-SW at the west of the Goksun bend and the strand divides into several splay in NE-SW trending in the Adana basin. Our data reveal that the northern strand of the EAF also is played an important role in the active deformation of the Eastern Mediterranean. GPS measurements indicate that slip rate along the EAF increase from southwest to northeast. We can speculate that there might be a slip partitioning between the southern and northern strands of the EAF west of Celikhan. The southern and northern strands accommodate ratio of the 2/3 and 1/3 slip-rate of the fault zone respectively. We also suggest that EAF and DSF connected to each other by the Turkoglu bend at the north of the Karasu rift valley.