Near-surface, 'Thin Skin' reverse faulting stresses in the Southeastern United States

Hydraulic fracturing stress measurements have been conducted in crystalline rock at two locations within the southeastern United States at depths from 50 meters to more than one kilometer. Stress orientations are similar to those obtained from other local and regional stress indicators and are consistent with a ridge-push source of intraplate stress. High horizontal stress magnitudes (with respect to the vertical stress) are found only in the near-surface. Thus, although relatively shallow stress orientation measurements appear to be reliable indicators of the stress orientation at greater depth, stress magnitudes cannot be extrapolated quantitatively beyond the depth range of the measurements.