Deciphering of karst geomorphology and sinkhole (doline) structures using multiple geophysical and geological methods (Trabzon, NE Türkiye)

To date, in Türkiye only a limited number and volume of combined geophysical and geological studies about karst have been performed. In this study, karstification and geomorphological features were examined with geophysical and geological methods together and initial results were obtained for Türkiye. Although the geology of the limestone forming the Şahinkaya Member, which contains Çayırbağı, Çalköy, and Çal Cave, near the Düzköy district of Trabzon/Türkiye province was studied by many researchers to date, there is no geophysical study to determine the internal structural features, groundwater, dolines, and karstic voids. The aim of this study was to identify karst formations and their structural extensions in Şahinkaya Member with geophysical methods. Therefore, three different study locations with a total surface area of approximately 3.2 km 2 were examined with electrical resistivity tomography, self-potential, seismic refraction tomography, multichannel analysis of surface waves, and ground penetrating radar. These geophysical applications in limestone helped to identify karst cavities, water-saturated zones and dolines. Finally, the order of priority and efficiency of the five applied geophysical methods was compared, and the stages of the applications were outlined. In addition, the origin of karstification in the area investigated in this study was supported by petrographic, petrophysical and rock mechanic data.