Surface heat flow in Western Anatolia (Turkey) and implications to the thermal structure of the Gediz Graben

Abstract

Knowledge of heat flow density on the Earth's surface and subsurface temperature distribution is essential for the interpretation of several processes in the crust such as for the evaluation of the geothermal potential of a region. With this study, we investigate the conductive heat flow distribution in western Anatolia to understand the thermal state and its relationship to regional tectonics in the region. The new heat flow data are collected and combined with previously published data to obtain the new heat flow map of western Anatolia. Analysis of data sets after appropriate corrections yields a better picture of the regional distribution of heat flow within the region. Generally, high values are observed around the grabens of Menderes Massif due to the intense tectonic activity. We also present the 2D steady-state thermal model of Gediz. The modeled temperatures are validated by temperature measurements from two deep wells. Numerical 2 simulation results show that the dominant heat transfer mechanism in Gediz graben can be explained by conduction. Temperature distribution in the deep subsurface of the graben is controlled by both thickness distribution and thermal properties of the different stratigraphic sections. Thermal conductivity contrast between different stratigraphic sections causes anomalously elevated heat flow values at the edges of the graben. The comprehensive results of this study will bring a new perspective to geothermal studies in particular Enhanced Geothermal Systems (EGS) resource estimations in Gediz graben.

Ambient noise tomography of the Aegean region of Türkiye from Rayleigh wave group velocity

“…For comparison, a tomographic image of the surface group wave velocity obtained from this study for 2 s period (Figure 8A) is shown together with Bouger gravity anomaly (Figure 8B), heat flow (Figure 8C), and magnetic (Figure 8D) results reported by Gonenc et al, 2012, Pamukcu et al, 2019, Pazvantoglu et al, 2021Teknik et al, 2023. We interpret the low velocity zones in offshore areas (e.g., IB, CB) as sedimentary sequences overlying a Miocene basement. The size of the IB low velocity zone is 50 × 20 km (Figure 8A).…”

“…The Aegean region of Türkiye is affected by frequent seismic activity, mostly of low magnitude (Coban and Sayil, 2019;Ozturk, 2019;Ankaya Pamukcu et al, 2021), and shows high heat flow (Pazvantoglu et al, 2021) and geothermal activity (Ozer and Polat, 2017a). Only few moderate earthquakes have been recorded in the study area (e.g., Mw6.2 Lesvos-Izmir earthquake on 12 June 2017, Mw6.5 Bodrum-Kos earthquake on 21 July 2017).…”

“…FIGURE 8Maps for; (A) Surface group velocity of this study, (B) Gravity anomaly(Gonenc et al, 2012), (C) Heat flow(Pazvantoglu et al, 2021), and (D) Magnetic(Teknik et al, 2023).…”