Meaning of the Küçük Menderes graben in the tectonic framework of the central Menderes metamorphic core complex (western Turkey)

Unusually steep, high-angle south-dipping normal faults, that separate the metamorphic rocks of the Menderes massif from the Neogene sedimentary deposits, occur in the northern Küçük Menderes graben in western Turkey. These faults probably reached their current position as a result of the special tectonic framework of the central Menderes metamorphic core complex. This area experienced further exhumation along with the rolling hinges of faults limiting Alasehir and Büyük Menderes grabens, giving rise to a huge syncline in the region. This regional structure would be most likely responsible for the present position of the high-angle graben bounding normal faults that rotated along a horizontal axis. However, recent studies in the same area claim for the development of reverse faulting between the metamorphic basement and the Neogene sedimentary units, and present this observation as evidence for a supposed Miocene-Pliocene regional contractional regime in western Turkey. Even if these reverse faults or other post-Miocene contractional structures existed in the central Menderes massif, they would not afford evidence of regional contraction since its generation could be related to the contractional area that would have developed along the axial zone of the huge syncline in the central Menderes massif, in its turn resulting from a regional extensional process that took place during the further exhumation stage

Meaning of the Küçuk Menderes graben in the tectonic framework of the central Menderes metamorphic core complex (western Turkey)

Unusually steep, high-angle south-dipping normal faults, that separate the metamorphic rocks of the Menderes massif from the Neogene sedimentary deposits, occur in the northern Küçük Menderes graben in western Turkey. These faults probably reached their current position as a result of the special tectonic framework of the central Menderes metamorphic core complex. This area experienced further exhumation along with the rolling hinges of faults limiting Alasehir and Büyük Menderes grabens, giving rise to a huge syncline in the region. This regional structure would be most likely responsible for the present position of the high-angle graben bounding normal faults that rotated along a horizontal axis. However, recent studies in the same area claim for the development of reverse faulting between the metamorphic basement and the Neogene sedimentary units, and present this observation as evidence for a supposed Miocene–Pliocene regional contractional regime in western Turkey. Even if these reverse faults or other post-Miocene contractional structures existed in the central Menderes massif, they would not afford evidence of regional contraction since its generation could be related to the contractional area that would have developed along the axial zone of the huge syncline in the central Menderes massif, in its turn resulting from a regional extensional process that took place during the further exhumation stage

The 2005 - 2007 Bala (Ankara, central Turkey) earthquakes : a case study for strike-slip fault terminations

An intense seismic activity has been observed after the Bala (Ankara, NW central Turkey) earthquakes (30 July 2005: Mw=5.3, 20 December 2007: Mw=5.4, and 26 December 2007: Mw=5.3), continuing up to the present. The epicenters and the focal mechanism solutions of the earthquakes indicate that the right lateral strike-slip Afşar fault, trending N55-60°W, is responsible for the main shocks. The Afşar fault is thought to be the NW continuation of the Tuzgölü fault zone, which is one of the main neotectonic elements in central Anatolia. On the other hand, the aftershock distributions of the 2005 event have a NNE trend, and those of the 2007 event show a NW trending. Some focal mechanism solutions of the 2005 Bala earthquake aftershocks indicate normal and oblique normal faulting that corresponds to the NNE-trending Karakeçili fault. It seems that seismic activation of the NNE-trending Karakeçili fault was triggered by the 2005 main shock (Mw=5.3) that occurred on the NW-trending right lateral strike-slip Afşar fault. The overall neotectonic framework is that the northwestern edge of the Tuzgölü fault zone, represented by the Afşar fault in Bala, terminates in an extensional system represented by the oblique-slip Karakeçili faul

Meaning of the Küçük Menderes graben in the tectonic framework of the central Menderes metamorphic core complex (western Turkey)

Unusually steep, high-angle south-dipping normal faults, that separate the metamorphic rocks of the Menderes massif from the Neogene sedimentary deposits, occur in the northern Küçük Menderes graben in western Turkey. These faults probably reached their current position as a result of the special tectonic framework of the central Menderes metamorphic core complex. This area experienced further exhumation along with the rolling hinges of faults limiting Alasehir and Büyük Menderes grabens, giving rise to a huge syncline in the region. This regional structure would be most likely responsible for the present position of the high-angle graben bounding normal faults that rotated along a horizontal axis. However, recent studies in the same area claim for the development of reverse faulting between the metamorphic basement and the Neogene sedimentary units, and present this observation as evidence for a supposed Miocene-Pliocene regional contractional regime in western Turkey. Even if these reverse faults or other post-Miocene contractional structures existed in the central Menderes massif, they would not afford evidence of regional contraction since its generation could be related to the contractional area that would have developed along the axial zone of the huge syncline in the central Menderes massif, in its turn resulting from a regional extensional process that took place during the further exhumation stage

Determining The Main Strand Of The Eskisehir Strike-Slip Fault Zone Using Subsidiary Structures And Seismicity: A Hypothesis Tested By Seismic Reflection Studies

The Eskisehir Fault Zone is one of the major neotectonic structures of Turkey, extending from Inegol (Bursa) to Cihanbeyli (Konya). The fault zone presents a considerable seismic risk for the city of Eskisehir but the exact locations of active segments and the source of the major seismic event, the 1956 earthquake (M = 6.5) that occurred in the instrumental period (from 1900 to 2013), have been debated in recent literature. The structural data obtained from field studies indicate an approximately N60W-trending main strand of the right lateral strike-slip Eskisehir Fault Zone. This trend corresponds to the en echelon bends on the course of the Sarisu River. Using this concurrence, the positions of Bahcehisar and the Cukurhisar-Sultandere segments are proposed and checked by seismic reflection studies. The seismic sections disclosing positive flower structures confirm the hypothesized position of the Cukurhisar-Sultandere segment. The relocation of epicenters and focal mechanism solutions of seismic events in 1956, 1990, 2010, and 2013 indicate that the Cukurhisar-Sultandere segment might be the rupture source of the 1956 event and is a possible potential seismic source for an earthquake that could seriously affect the Eskisehir settlement.WoSScopu