The ilica branch of the southeastern eskişehir fault zone: An active right-lateral strike-slip structure in central Anatolia, Turkey

Abstract

The Eskišehir Fault Zone is one of the prominent neotectonic structures of Turkey. It separates the west Anatolian extensional province and the strike-slip induced northwest central Anatolian contractional area in the Anatolian Block. Its southeastern part is generally divided into three branches, namely the Ilica, Yeniceoba, and Cihanbeyli from north to south, respectively. The right lateral strike-slip Ilica branch (IB) is an approximately 100-km-long fault and it is composed of several segments in a northwest-southeast direction. The slickensides, subsidiary fractures, cataclastic zone, fracture-controlled drainage pattern, right lateral stream deflections, deformation in the Quaternary unit observing in the seismic reflection sections, and seismicity of the region all indicate that the IB is an active right lateral strike-slip fault. The IB has also a regional tectonic importance as a boundary fault between the contractional and the extensional regions in central Anatolia considering that it is the southern limit of the contraction-related structures in the west-southwest of Ankara.