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. | Turkish Journal of Earth Sciences Turkish J Earth Sci 2021 30 991-1007 http earth TÜBİTAK Research Article doi yer-2105-28 Surface heat flow in Western Anatolia Turkey and implications to the thermal structure of the Gediz Graben 1 2 1 3 2 Elif BALKAN-PAZVANTOĞLU Kamil ERKAN Müjgan ŞALK Bülent Oktay AKKOYUNLU Mete TAYANÇ 1 Department of Geophysical Engineering Dokuz Eylül University İzmir Turkey 2 Department of Environmental Engineering Marmara University İstanbul Turkey 3 Department of Physics Marmara University İstanbul Turkey Received Accepted Published Online Final Version 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 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