Süha Özden

Kinematics of the East Anatolian Fault Zone between Turkoglu (Kahramanmaras) and Celikhan (Adiyaman), eastern Turkey

In this study we determined the stress regime acting along the East Anatolian Fault Zone between Turkoglu (Kahramanmaras) and Celikhan (Adiyaman), from the Neocene to present-day, based on the inversion of striations measured on faults and on the focal mechanisms of earthquakes having magnitudes greater than 5.0. The inversions yield a strike-slip stress regime with a reverse component (i.e., transpression) operative in the Neocene to present with a consistent N-to NW-trending σ1 axis 156 ± 11° and an E- to NE-trending σ3 axis, 67 ± 9°σ3, producing left-lateral motion along the East Anatolian Fault Zone. The inversions of focal mechanisms yield a strike-slip stress deviator characterized by an approximately N-S (N89°W)-trending σ1 and an approximately E-W (N89°E)-trending σ3 axis. Both the kinematic analysis and structural observations indicate that the stress regime operating in the study area has had a transpressional character, giving rise to the Mio-Pliocene compressive structures (reverse faults, thrusts and folds) observed in the study area. Field observations allow estimation of a Pliocene age for the strike-slip East Anatolian Fault Zone.

Plio-Quaternary stress regime in Eşen Çay Basin, SW Turkey

Abstract The Plio-Quaternary Eşen Çay Basin is situated at the junction of Hellenic and Cyprus arcs in southwestern Turkey. The basin is important for understanding the tectonic evolution of the region in relation to the Hellenic and Cyprus arcs. Fault data from unconsolidated Pliocene and Quaternary deposits, as well as from pre-Pliocene lithologies, are analysed in order to reconstruct the evolution of the stress field evolution from Pliocene onwards. Inversion of measured fault slip vector data identifies two main stress states: extensional and strike-slip. Both states are characterized by a NE–SW-trending minimum horizontal stress axis (σHmin=σ3). The mean R value is 0.67, indicating a triaxial state of stress. The inversion also indicates the existence of extensional and strike-slip faulting characterized by a NW–SE-trending σ3 axis. This indicates a change in the direction of the minimum horizontal stress axis (σ3) from a NW–SE-trending σ3 that dominated prior to Quaternary to a NE–SW-trending σ3 that dominated during Quaternary up to actual time.

Classification of residential areas according to physical vulnerability to natural hazards: A case study of Çanakkale, Turkey

The selection of new settlement areas and the construction of safe buildings, as well as rendering built-up areas safe, are of great importance in mitigating the damage caused by natural disasters. Most cities in Turkey are unprepared for natural hazards. In this paper, Çanakkale, located in a first-degree seismic zone and sprawled around the Sartçay Delta, is examined in terms of its physical vulnerability to natural hazards. Residential areas are analysed using GIS (geographic information system) and remote-sensing technologies in relation to selected indicators. Residential areas of the city are divided into zones according to an evaluation of geological characteristics, the built-up areas features, and urban infrastructure, and four risk zones are determined. The results of the analysis show that the areas of the city suitable for housing are very limited. In addition, the historical centre and the housing areas near Sartçay stream are shown to be most problematic in terms of natural disasters and sustainability.

An active extensional deformation example: 19 May 2011 Simav earthquake (Mw = 5.8), Western Anatolia, Turkey

The Simav Earthquake that occurred on 19 May 2011 in western Turkey was investigated on the basis of seismological data and geological observations. Approximately WNW?ESE trending surface ruptures were observed on the Simav Fault. The focal mechanism parameters of the earthquake (Mw = 5.8) and its aftershocks (Mw??>??3.5) were estimated using time-domain moment tensor inversion. A total of 2245 events were located with Geiger?s conventional absolute location method then relocated using the double difference (DD) algorithm. The calculated locations at a depths between 2 and 16?km were found to be consistent with Coulomb stress variation in the area. Average variance reduction (VR) of the solutions was calculated as ~70%. The focal parameters of strike dip and slip of the main shock, occurring at a depth of 11?km dipping towards the NNE, were estimated at 277, 62 and ?92, respectively. The most striking indication of the study is that the area is dominated by normal faults with mainly WNW?ESE trends. It is also concluded that earthquakes in the region are caused by an active and regional NNE?SSW (N 12? E) trending (?3 axis) extension regime. The mean stress ratio is 0.80, indicating a triaxial stress state. This extension is probably associated with a slab?pull force and /or roll-back due to the complex subduction process of the African Plate beneath Anatolian block along both the Hellenic and Cyprus arcs in the eastern Mediterranean region.

An Assessment of the Earthquakes of Ancient Troy, NW Anatolia, Turkey

According to the intermittent archeological excavations, carried out from 1871 up to the present, there exist nine different layers of settlements in Troy. Although there is some archeological evidence which indicates that some of these layers, especially Troy III (B.C. 2200‐2050) and Troy VI (B.C. 1800‐1275) have been damaged by one or more earthquakes, no multidisciplinary geoscientific research has been carried out so far on the active faults which could have caused these earthquakes.