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An active fault is a fault that is likely to become the source of another earthquake sometime in the future. Geologists commonly consider faults to be active if there has been movement observed or evidence of seismic activity during the last 10,000 years. [1] Active faulting is considered to be a geologic hazard – one related to earthquakes as
Some use the term "transform fault" to describe the seismically and tectonically active portion of a fracture zone after John Tuzo Wilson's concepts first developed with respect to the Mid-Atlantic Ridge. [2] The term fracture zone has a distinct geological meaning, but it is also used more loosely in the naming of some oceanic features.
Also called Indianite. A mineral from the lime-rich end of the plagioclase group of minerals. Anorthites are usually silicates of calcium and aluminium occurring in some basic igneous rocks, typically those produced by the contact metamorphism of impure calcareous sediments. anticline An arched fold in which the layers usually dip away from the fold axis. Contrast syncline. aphanic Having the ...
View of Doso Doyabi, Snake Range, Nevada, which was formed by detachment faulting. A detachment fault is a gently dipping normal fault associated with large-scale extensional tectonics . [ 1 ] Detachment faults often have very large displacements (tens of km) and juxtapose unmetamorphosed hanging walls against medium to high-grade metamorphic ...
In geology, a fault is a planar fracture or discontinuity in a volume of rock across which there has been significant displacement as a result of rock-mass movements. Large faults within Earth 's crust result from the action of plate tectonic forces, with the largest forming the boundaries between the plates, such as the megathrust faults of ...
Tilted block faulting, also called rotational block faulting, is a mode of structural evolution in extensional tectonic events, a result of tectonic plates stretching apart. [ 1 ] [ 2 ] When the upper lithospheric crust experiences extensional pressures, the brittle crust fractures, creating detachment faults . [ 3 ]
Types of faulting. Anderson's theory of faulting, devised by Ernest Masson Anderson in 1905, is a way of classifying geological faults by use of principal stress. [1] [2] A fault is a fracture in the surface of the Earth that occurs when rocks break under extreme stress. [3] Movement of rock along the fracture occurs in faults.
The term also applies to a line plotted on a geological map to represent a fault. These fractures tend to occur when a slip surface expands from a fault core, especially during an earthquake . This tends to occur with fault displacement, in which surfaces on both sides of a fault, known as fault blocks , separate horizontally or vertically.