The aim of the Master Thesis was to perform structural investigation/analysis of the western Papuk for HyTheC project supported by Croatian Science Foundation. In this work, principal research objectives were structural analysis of Mt. Papuk western margin, and construction of 3D geological model of research area. The conceptual 3D model was created in the Move program and it was constructed on the basis of i) interpreted geological cross sections placed perpendicular to the structures and ii) interpreted seismic reflection profiles. Five subparallel regional cross sections indicate the structural depression in the vicinity of Daruvar, whereas towards northeast it transient to western slopes of Mt. Papuk. For the purpose of construction of structural-geological profiles and correlative deformed deposits, structural-geological field observations were conducted, whereas analyses of structural measurements were conducted in Stereonet and Win-Tensor softwares. The constructed geological model suggests the existence of three tectonic phases, that in first phase accommodated formation of regional E-W oriented compressive structures (thrusts belts) characterized by tectonic transport top to the NW, whereas in the second and third tectonic phases, compression and transpression prevail. Tectonic movements are associated to the stress fied characterized by principal stress axis E-W and NE-SW that resulted with formation of N-S oriented synclines and anticlines and sinistral/dextral translational/ rotational structures respectively. Conducted investigation in Daruvar area was performed in order to address subsurface structural relationships that may pinpoint factors, which affect the discharge and recharging of the carbonate aquifer of thermal water found in Daruvar.