Fault core/damage zone; an unhelpful description of fault zone structure?



Childs, C., Manzocchi, T., Walsh, J.J. & Schöpfer M.P.J.1
1 - Present Address: Department for Geodynamics and Sedimentology, University of Vienna, Althanstrasse 14, A-1090 Vienna, Austria.

Abstract - The standard outcrop description of fault zones currently in vogue is a high strain fault core containing fault rock surrounded by a low strain halo termed a damage zone. This description does not acknowledge the significance of fault segmentation or displacement partitioning within fault zones and therefore fails to capture features which are crucial for defining the flow charateristics of faults. This terminology derives from outcrop studies but it is limited in it's ability to describe faults in 3D. Outcrop studies can best contribute towards an understanding of fault zones if they are set in the context of an appropriate 3D appreciation of faults, including quantitative definition of internal displacements and strain. Fault terminology should be guided by those datasets where 3D fault zone structure can be deciphered rather than by what is convenient in outcrops where it cannot. We suggest that the damage zone/fault core description promotes not only a simplified view of faults, but also a misleading one which is an obstacle to understanding them.

Abstract of talk given to:

Fault and Top Seals, EAGE Conference, Montpellier, September 2012.