FAULT TERMS, COMMON STRIKE SLIP

strike-slip fault: technically only refers to orientation of net slip vector, hence the fault could be shallowly dipping.

wrench fault - vertical strike-slip fault (what people usually are thinking about when they say strike-slip fault).

transcurrent fault - big wrench fault.

transform fault - lithospheric in dimension.

en echelon - refers to a stepped pattern. Consistently oriented structures, within but consistently oblique to enveloping surfaces

TERMS: strike-slip, wrench, transcurrent faults; orogen parallel motions en echelon structures Wilcox et al. model of en echelon structures: card decks and clay models block and structure rotations restraining and releasing bends transpression and transtension positive and negative flower structures Dead Sea Rift San Andreas Alpine fault, S Island New Zealand Spitsbergen's Tertiary fold-thrust belt deformation partitioning / decoupling and weak surfaces Transpression and transtension and flower structures:

Defined in cross section perspective:

faults steepen with depth.

faults are predominantly strike-slip, but with a consistent dip-slip component.

steep portion often not well imaged seismically.

consideration of 3-d deformational balancing.

Flower structures as local shallow strike-slip duplexes.

Models of decoupling:

The basic idea is that if there are transpressional or transtensional conditions, an alternate response is to have the strike-slip and dip-slip components accommodated on separate but parallel structures. Instead of a positive flower structure you could have a parallel set of thrusts and vertical strike-slip faults. This can be approached from an energy perspective.

Decoupling is promoted when a very weak slip surface is involved. This can be a previously existing surface or develop with deformation.

This behavior had been modeled in laboratory studies.

Oblique subduction zones often shows this behavior at a large scale.