UTIG Seminars

When:    Monday, April 27, 2009 10:30 a.m. to 11:30 a.m.
Where:   Seminar Room 1.603, 10100 Burnet Road, Bldg 196-ROC, Austin, Texas 78758
Host:     Sean Gulick, UTIG

Since the classic 1959 paper of Hubbert & Rubey, pore-fluid pressures in excess of hydrostatic have been considered to play a dominant role in thrust mechanics by weakening both thrust sheets and their basal detachments, with the weakening of the detachment dominating. We examine these two classic roles of pore-fluid pressure in thrust mechanics, showing that in many cases that the classic Hubbert-Rubey hypothesis fails quantitatively as the primary cause of extreme fault weakness but is a likely major control of crustal strength, or strength of thrust belts and extensional margins. We use these results to develop new ideas about how to parameterize the mechanics of accretionary wedges and deep-water thrust belts in terms of observable quantities, including borehole data and seismic velocities. This is important because studies of the mechanics of accretionary wedges, and indeed of mountain belts more generally, have been held back to a considerable degree by the difficulties in obtaining deep observational constraints on the mechanical state of actively deforming regions. We apply these concepts to a number of actively deforming regions, including examples from Taiwan, Barbados, Nankai trough, Niger Delta, Brunei Delta and Brazos area offshore Texas.