## 3 Geological Data Interpretation
Legend: 1—Regional geological structural units: a—Adriatic microplate (AMP) and Adriatic (A) unit, b—Southern Alps (SA), Eastern Alps (EA), Prealps (AF) and Sava faults (SF), c—Dinarides, and Dinarik (D) and Supradinarik (SD) units, d—Pannonian Basin: Western (WPB) and Southern (SPB); 2—major faults adjacent to regional structural units: Trieste–Ucka–Vis fault (1), Iirska Bistrica–Rijeka–Vinodol fault (3), Fella–Sava fault and continuation of Ljubljana–Karlovac–Slunj (5), southern boundary fault of Pannonian Basin (6), SA fault (7), Zagreb fault (8), Periadriatic fault and continuation of Drava fault (9); 3—other important faults; 4—reverse faults; 5—faults of indeterminate character; 6—the direction of horizontal movement along the fault; 7—movement direction of the Adriatic microplate (AMP); 8—direction of annual velocity at geodetic points in mm/yr. (**b**) Seismic activity: 1a—major faults: Ljubljana–Karlovac–Slunj fault (5), Zagreb fault (8), Periadriatik fault and continuation of Drava fault (9); 1b—other important faults bordering seismotectionically most active structural units in the western part of the Pannonian basin (WPB); 2—the direction of horizontal movement along the fault; 3—earthquake epicentres (a) and earthquake magnitudes (b). Two observations should be noted. First, the inclination angles of the velocity directions determined at the geodetic stations shown in Figure 3 are notable. In the Drava Basin (16), the eastern part of the Sava Basin (14), and the central part between the elevated structural units, the velocity directions (inclinations) are almost horizontal. In the zones of the Drava fault (9), Zagreb-Vinkovci fault (11), and especially the Barch-Baranja fault (12), there are elevations with angles greater than \(30^{\circ}\) and \(60^{\circ}\). This points to tectonically active fault sections and the elevation of structures. Furthermore, reverse movements along the Zagreb-Vinkovci fault (11), mostly toward the SW, are signs of resistance to the regional tectonic movements identified at the geodetic points. This indicates space compression. However, in the Sava fault (10) and especially along the Drava fault (9), the directions of the geological and geodetic movements are identical. This shows the contact of rocks with different densities. This is the case when there are primary reverse movements and a sudden sloping elevation of higher density rocks toward the surface. They then coincide with the regional directions of the tectonic movements. An example is the seismic reflex profile over Bilogora (13) shown in Table 1.2 The position of the Paleozoic rocks at depth is essential. There is a noticeable and gradual reverse in the rise of the rocks toward the NE. In the zone of the Drava fault (9a,b), this is followed by an abrupt discontinuance and lowering of the rocks in depth. Table 1.3 Recent geological structural setting and tectonic activity in the area of the Pannonian Basin. Legend: 1—Regional geological structural units: Pannonian Basin: Western (WPB), Southern (SPB), and Central (CPB); 2—the most prominent structural units within the regional geological structural units along whose wings are reverse faults of opposite vergence: Petrova gora –Kozara (7), Zumberak–Medvednica (8), Vukomericke gorice–Samarica (9), Moslavacka gora Gora (10), Psunj–Dilj gora (11), Papuk (12), and Bilogora (13); 3—large basins: Sava (14), Mura (15), and Drava (16); 4—major faults adjacent to regional structural units and the Sava and Drava Basins: the southern boundary fault of the Pannonian Basin, Zagreb fault (8), Peridariatic fault and continuation of the Drava fault (9), Sava fault (10), Zagreb–Vinkovci fault (11), and Barcs–Baranja fault (12); 5—other important faults; 6—reverse faults; 7—faults of indeterminate character; 8—direction of horizontal movement along the fault; 9—direction of movement of parts of structures along the surface according to geological data; 10—direction of annual velocity at geodetic points in mm/yr.