Geothermal investigations in western Anatolia using equilibrium temperatures from shallow boreholes

Abstract

Abstract. Determination of the conductive heat flow in western Anatolia has broad implications in many areas, including studies on the present-day extensional tectonic activity and assessments of the geothermal resources in the region. In this study, high-resolution equilibrium temperatures from 113 boreholes with depths of ∼ 100 m were analyzed for determination of the conductive heat flow. Thermal conductivities were either determined by measurements on outcrops or estimated using lithologic records. By a detailed analysis of temperature-depth curves, a total of 55 sites were selected as being useful for further conductive gradient/heat flow calculations, while the remaining 58 sites were abandoned due to hydrological effects on temperatures. Heat flow values with formal errors were calculated for 24 sites where rock thermal conductivity information is available. Due to the shallow depths of the investigated boreholes and uncertainties in thermal conductivity information, the results include a large accumulated error. A preliminary heat flow map is generated using the results of this study and a previous study in the southern Marmara region. is not observed in the region. The heat flow values reported in this study are comparable to the previously reported values in the Aegean Sea, as the two regions form the back-arc section of the Hellenic subduction zone.

Deep structure of the Hellenic lithosphere from teleseismic Rayleigh-wave tomography

“…In the following paragraphs we focus on the main structures which are sufficiently resolved by the depth inversion of the Helmholtz phase-velocities: (a) the oceanic-continental lithosphere transition, (b) slab segmentation, (c) lithospheric thickness and the arrangement of the asthenosphere. These issues are discussed in juxtaposition with information on the distribution of subcrustal seismicity (catalogues compiled in this study), volcanism (Siebert & Simkin, 2002;Serpen et al 2010;Erkan, 2015) and the crustal stress-field inferred from the inversion of focal mechanisms .…”

“…14). (Siebert & Simkin, 2002;Serpen et al 2010;Erkan, 2015). Black solid lines indicate profiles of cross-sections shown in Fig.…”

“…13) are correlated with low-enthalpy (e.g. Paiko volcano, Andritsos et al 2011) and remnant volcanism (thermal springs) in N. Aegean and NW Anatolia (Siebert & Simkin, 2002;Serpen et al 2010;Erkan, 2015).…”

Investigating P- and S-wave velocity structure beneath the Marmara region (Turkey) and the surrounding area from local earthquake tomography

“…The observed anomalies seem remarkably consistent with the known geologic features and tectonic evolution of the region and the surrounding area. Recently, in the interior of the southern Marmara region, one of the studies conducted by Erkan (2015) shows moderate heat-flow values. As known, the heat flow remarkably influences seismic velocities.…”

Three-Dimensional Seismic Velocity Structure of the Aegean Region of Turkey from Local Earthquake Tomography

“…Moreover; geological/tectonic structures, geothermal resources, petrological properties of rocks and volcanoes can be identify using Local Earthquake Tomography (LET) method [Yang and Shen 2005, De Matteis et al 2008, Kaypak 2008, Berger et al 2011, Hofstetter et al 2012, Yolsal-Cevikbilen et al 2012, Del Pezzo et al 2013, Muksin et al 2013, Abril et al 2016, Ozer and Polat 2017a. Studies [Kaypak and Gokkaya 2012, Komut et al 2012, Erkan 2015, Bilim et al 2016] on the crustal structure and geothermal potential of western Anatolia emphasise that different perspectives of the studies are still needed in the study area. Therefore; we used local earthquake tomography method to understand the crustal structure and geothermal potential of the Aegean region of Turkey.…”