Abstract:

In this article, the temporal and spatial development of probable sinkholes in the close vicinity of a couple of sinkholes that occurred in 2007 and 2018 in the Kozaklı (Nevşehir) geothermal field, which is one of the most important thermal tourism centers where treatment with radon gases and mud can be carried out in Central Anatolia, was investigated using the multi-electrode resistivity method and core drilling data. The primary geothermal water aquifer consists of Palaeozoic aged marbles, the secondary Eocene aged limestone aquifer and cover rocks are the impermeable units of the area. Geothermal waters gain heat by geothermal gradient, granitic intrusions, and radiogenic ways. The depths, temperatures, and pH values of the wells belonging to geothermal water resources vary between 60 and 1493 m, 45 and 96 °C, as well as 6.22 and 6.61, respectively. Two-dimensional electrical resistivity methods were used to determine the dimensions of the collapse structures. In the geophysical studies examining the depths of 15-30 meters, surface fractures around the sinkhole, a subsidence structure nearby the active highway approximately 20 meters to the east, travertine was found around the pothole, especially in the east and north of the hollow structure. This data verified with log data obtained from core drilling. These findings are indicators for the ongoing karstification process.

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