## 6 Conclusions  
The geothermal aquifer of the Humenne Unit is linked to the distribution of the Middle Triassic carbonates, which are distributed irregularly throughout the unit. Differences in the thickness of the aquifer are the result of Miocene deformation along the Klippen Belt. The deformation level changes depend on the distance from the accretionary edge (Klippen Belt) and have a direct effect on permeability and porosity. The overall low permeability forces us to use the most optimal structures (like tectonic elevations in the subsurface) so that we may increase the temperature and the yield rate. Their exploration is possible via multiple geophysical methods, of which seismic cross-sections and gravimetry dominate. Using the individual geophysical methods, the following conclusions were reached:  
* Deep seismic cross-sections are the most precise sources of information from the subsurface. Based on their interpretation it was possible to distinguish the basic sedimentary boundaries, the relationship between volcanic complexes and sediments, tectonic structures, and individual geological forms. They are also the starting point for other already mentioned geophysical methods. The biggest disadvantage is the cost of making deep seismic profiles.
* The calculation of the Complete Bouguer anomaly determined the numerical values of the density anomalies that correspond to the morphological elevations and depressions of the pre-Cenozoic basement. The study area, represented by volcanic (Moicene) and sedimentary rocks (Mesozoic-Cenozoic), had a reduction density of 2.67 g\(\cdot\)cm\({}^{-3}\).
* Geoelectric resistivity profiling has some limits. Geoelectric resistivity layers are possible to interpret to a maximum depth of 500 m. There are 4 layers with specific resistivity values in the study area:  
\(\rho\): 4-50 \(\Omega\)m--intensely aquifers andesites, breccias, tuffs/clays, marly limestones  
\(\rho\): 30-60 \(\Omega\)m--marly limestones, shales, clays  
\(\rho\): 50-200 \(\Omega\)m--andesite lava flows, breccias  
\(\rho\): 80-360 \(\Omega\)m--mainly carbonates, compact andesites  
The specific heat-energy potential has a wide range of 0.337-19.533 GJ/m\({}^{2}\). The highest values above 15 GJ/m\({}^{2}\) are reached in areas where the temperature on the surface of Triassic carbonates exceeds 90 \({}^{\circ}\)C.  
The aquifer of the Humenne Unit has significant geothermal, hydrological, and geological limitations. However, low-temperature sources have future potential. Similar low-permeability structures are quite common worldwide, as opposed to huge geothermal areas. Their exploration combined with other green power sources could be an opportunity for the region's development.  
**Author Contributions:** Conceptualization, S.J. and Z.B.; methodology, S.J.; software, R.F.; validation, S.J., Z.B. and A.D.T.; formal analysis, R.F.; investigation, S.J.; data curation, V.B.; writing--original draft preparation, S.J.; writing--review and editing, A.D.T.; visualization, A.D.T.; supervision, R.F.; project administration, Z.B. All authors have read and agreed to the published version of the manuscript.  
**Funding:** This work was supported by the Ministry of Environment of the Slovak Republic No.2003/094.  
**Institutional Review Board Statement:** Not applicable.  
**Informed Consent Statement:** Not applicable.  
**Data Availability Statement:** All data are presented in this article in the form of figures and tables.  
**Conflicts of Interest:** The authors declare no conflict of interest.