straindominated

Strain-dominated is a term used in geology to describe a type of faulting where the deformation of rock is primarily controlled by the stretching or thinning of the crust. This occurs in extensional tectonic settings, where the crust is being pulled apart. In such environments, faults are typically normal faults, which are characterized by a dip-slip movement where the hanging wall moves down relative to the footwall. The strain-dominated regime is often associated with the formation of rift valleys and grabens, which are linear depressions bounded by faults.

The term "strain-dominated" contrasts with "stress-dominated" regimes, where the deformation is primarily controlled by the compression of the crust, leading to the formation of thrust faults and fold-and-thrust belts. The transition between these two regimes can be influenced by factors such as the rate of extension or compression, the thickness of the crust, and the presence of pre-existing structures.

Strain-dominated regimes are commonly found in areas of continental rifting, such as the East African Rift and the Basin and Range Province in the western United States. These regions are characterized by the presence of numerous normal faults, which accommodate the extension of the crust. The strain-dominated regime can also be observed in oceanic settings, where it is associated with the formation of oceanic spreading centers and transform faults.