--> ABSTRACT: The Geometric Strength of Fault Systems, by David A. Ferrill, Alan P. Morris, Darrell W. Sims, and John A. Stamatakos; #90906(2001)
[First Hit]

Datapages, Inc.Print this page

David A. Ferrill1, Alan P. Morris2, Darrell W. Sims1, John A. Stamatakos1

(1) CNWRA, Southwest Research Institute, San Antonio, TX
(2) Division of Earth and Physical Sciences, University of Texas at San Antonio, San Antonio, TX

ABSTRACT: The Geometric Strength of Previous HitFaultNext Hit Systems

Faults optimally oriented for slip within an ambient stress field are geometrically weak compared with other Previous HitfaultNext Hit orientations. Evolving Previous HitfaultNext Hit systems undergo changes that lead to both geometric strengthening and weakening of faults. Given a single stress regime, geometrically weak faults grow and accumulate displacement, and geometrically strong faults tend to be abandoned. This natural selection process results in a well-organized Previous HitfaultNext Hit pattern that reflects the ambient stress field. Initial Previous HitfaultNext Hit surfaces are often en echelon and not connected. These faults grow by segment nucleation, growth, and connection by curved propagation or connecting Previous HitfaultNext Hit formation. Previous HitFaultNext Hit propagation prior to linkage produces local perturbations that modify continuing Previous HitfaultNext Hit propagation. As Previous HitfaultNext Hit segments link, local stress field perturbations are relieved and certain Previous HitfaultNext Hit patches become geometrically stronger in the ambient stress field. These poorly oriented Previous HitfaultNext Hit patches are bypassed by newly formed cutoff faults that straighten the overall Previous HitfaultNext Hit surface. This process results in an active Previous HitfaultNext Hit surface that is smoother and geometrically weaker, and that has a smaller surface area. In addition, slip on an array of parallel normal faults progressively reorients Previous HitfaultNext Hit planes to shallower and less favorable dips, causing the initiation of new, more favorably oriented faults. Analyses of natural Previous HitfaultNext Hit systems from the Basin and Range Province illustrate this Previous HitfaultTop system evolution.

Work supported by the U.S. NRC (Contract NRC-02-97-009). This is an independent product of the CNWRA and does not necessarily reflect the views or regulatory position of the NRC.

AAPG Search and Discovery Article #90906©2001 AAPG Annual Convention, Denver, Colorado