As displacement is accumulated on a fault surface through time, deformation is generated in the volume surrounding the fault. Previous studies have tended to only look at parts of this entire fault system in isolation. This thesis is a systematic survey of fault zone architecture at millimeter to kilometer scales, which is linked to variations in fault displacement. Structural data and displacement variations have been measured from two isolated normal faults cutting the Jurassic Navajo Sandstone in the Chimney Rock fault array, Utah, USA. Both faults are approximately four kilometres long with maximum displacements of thirty metres. The faults are surrounded by deformation bands and slip-surfaces typical of deformation in high porosity sandstones. Deformation is seen ahead of the fault tip and to either side of the well-developed fault surface. On average, the width of this zone of deformation is twice the displacement on the main slip surface. This implies that while some deformation is generated ahead of the fault tip (a process zone) deformation is then continuously accumulated after a through-going fault surface has developed, intensifying and widening the zone of off-fault deformation. The latter is referred to as a kinematic damage zone. The relationship between off-fault deformation width and displacement is potentially useful for predicting fault zone architecture below seismic resolution. However the exact form of the scaling relationship is not well controlled and is expected to vary in different lithologies. The off-fault deformation consists of an orthorhombic pattern of deformation bands, with a low angle between strike sets. This can be attributed to a small component of along-strike extensional strain (due to variation in displacement along the fault) combined with larger extensions perpendicular to the fault.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:661873 |
| Date | January 1999 |
| Creators | Shipton, Zoe K. |
| Publisher | University of Edinburgh |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://hdl.handle.net/1842/12929 |
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