Stress rotation – impact and interaction of rock stiffness and faults

It has been assumed that the orientation of the maximum horizontal compressive stress (S.sub.Hmax) in the upper crust is governed on a regional scale by the same forces that drive plate motion. However, several regions are identified where stress orientation deviates from the expected orientation due to plate boundary forces (first-order stress sources), or the plate wide pattern. In some of these regions, a gradual rotation of the S.sub.Hmax orientation has been observed.