Geologic structures at the surface, that were created by tectonic processes, can give a reliable indication of the principle stress orientations. Geological structures such as the volcanic vent alignment and active vertical fractures are formed perpendicular to the minimum horizontal stress and parallel to the maximum horizontal stress (see Figure 18). | Geologic structures at the surface, that were created by tectonic processes, can give a reliable indication of the principle stress orientations. Geological structures such as the volcanic vent alignment and active vertical fractures are formed perpendicular to the minimum horizontal stress and parallel to the maximum horizontal stress (see Figure 18). |