Favourable conditions for geothermal energy were created in Turkey during its neotectonic episode from Neogene to Quaternary. This episode is characterized mainly by fluvio-lacustrine sedimentation and strike-slip tectonics with associated magmatism. Under these conditions, a great number of geothermal areas have formed in the neotectonic provinces in association with major tectonic features, including the North and East Anatolian Fault Zones (NAFZ and EAFZ, respectively). Today, the geothermal resources of Turkey are mainly located in the West Anatolian Extensional Province associated with the graben systems. However, the Central Anatolian Ova Neotectonic Province is considered as one of the most promising geothermal targets which are characterized by the presence of widespread hot dry rock systems. This study mainly aims to throw light on the possible potentiality of these resources at Kırşehir Block by emphasizing the neotectonic evolution of the country.

No abstract

<p>During the co-seismic development of a fault in lithological environments, regions containing cavities may form momentarily or permanently. In the tectonic shift zones, these pressure gaps lead to the formation of irregular new intermediate sediment zones, as infiltrate in to the gap, if the pressure perturbations are large. The semi-fluid sediment material and sea water enter through opening fault sector's surrounding sediments at the far place from dispersing fault energy burst. But pore water infiltration is independent about place of vomited energy burst. In some cases hard material which detached from fault wall or top sediment material, provide isolation lids, as obstacling on 'cell type empty interlaying gaps' at tectonic line. They can collapse again or stay as gap form for a long time with suction force after seismic activities by effects of gravitation or pressure perturbations. For durable gaps, pore water is capable to infiltrate in to the gap with long lasting suction forces.  In these regions, in contrast to gravitational folding or collapse structures, the partial sediment sequence may be drawn and folded into the area of the material with different or close lithological density value. Deformational variety of the displaced materials are related with physical properties of seismic event at opening sector such as friction, displacement parameters (velocity, time), dimensional parameters of gap, and water depth.  The main objective of the paper is to figure out all interference mechanisms about these zones (created by pressure perturbations), which develop rapidly during earthquake fractures (or in some cases fractures generated by impulsive pressure changes such as those created by volcanoes). Fracture of fault segments forms a complex mechanical system associated with bedrock, upper sedimentary sequence, and aquatic environment, depending on the location where they occur, even the atmosphere. Therefore, the displacement may be bi-directional to the lower slit or upward from the seabed during the opening or closing stages of the cavity, depending on the nature with variations of the atmosphere & water-sediment mixture. The strong (pulling or impulsive) pressure perturbation effect associated with permanent cavities caused by rapid breakage pulls the material that may form a sludge volcano or water outlet under deformation and brings the environment to near pressure equilibrium. This simple explanation can help to find real additional effective reason for the different formations of assumed collapse or folding structures created by gravitational movements in geology. The hypothesis after main objective at above mentioned in this article is based on the fact that the emergence of  escapes as squeezed fluid form  of water & sediment from compacted secondary irregularities in the previously broken fault segment will help to understand the next seismic mobility in other tectonic segments by identifying source depth cues through physical and chemical analysis. Geophysical instrumentation and applications are still need further developments of compact reflection line information, because the vertical thin anomalies mentioned in this paper are the most difficult structures for detection.</p>

Summary The westernmost segment of the North Anatolian fault in NW Turkey lies mostly offshore, in the Sea of Marmara and the Gulf of Saros (NE Aegean), respectively to the E and W of a 45 km inland central portion. The 9 August 1912 Mürefte-Şarköy (Ms 7.4) and 13 September 1912 (Ms 6.8) earthquakes occurred along this segment. To date, the segment was studied mostly onshore although estimated magnitude and location suggest an offshore extension. Recent studies show the eastern rupture extension in the Sea of Marmara, while its western counterpart in the Gulf of Saros remains less documented. Here we use new observations from high-resolution marine geophysical data (multibeam bathymetry, side-scan-sonar, and seismic reflection profiles), to constrain the offshore 1912 ruptures in the Gulf of Saros. Detailed mapping of the subaqueous fine-scale morphology and structure of the fault provides a new insight for the western limit of the two 1912 surface ruptures. Distribution of fresh scarps, 3D structural reconstructions, the complexity of fault segments, and the recent seismicity, altogether suggest that the western termination of the 1912 rupture(s) ends 37 km offshore in the Gulf of Saros. Following the 1999 Kocaeli earthquake, in the eastern Sea of Marmara, the unruptured segment length between the 1999 and 1912 ruptures became a critical issue, because of its implication for future earthquakes in the so-called Marmara seismic gap. If a 150-160 km total rupture length for the two 1912 earthquakes is assumed, a western rupture termination point at the inner Saros basin margin means that the eastern extension of the 9 August earthquake rupture reached the Central Marmara Basin. This outcome necessarily has implications for the seismic hazard in the Marmara coastal area that includes the Istanbul metropolitan area.