Influence of poroelastic behaviour on the magnitude of minimum horizontal stress, S _h , in overpressured parts of sedimentary basins

In many sedimentary basins of the world the minimum horizontal stress, S _h is greater in overpressured zones than in normally pressured zones at equivalent depths. A common explanation is that the frictional slip on listric normal faults keeps the difference between vertical stress, S _v , and S _h within certain bounds, and the difference is smaller under lower effective stress. However, in the overpressured parts of the central North Sea graben, United Kingdom, and the Sable subbasin of the Scotian Shelf, Canada, conventional friction envelopes underestimate the magnitude of S _h . It is argued that, whereas friction may govern S _h in normally pressured basins, poroelastic behaviour is responsible for the unusually high S _h in the overpressured parts of these same basins. -from Authors