Block diagram of a sheet shift.
Schematic animation of the sequence of movements on a right-handed (dextral) leaf displacement during an earthquake

A sheet displacement ( engl. : Strike-slip fault ), also transverse displacement , horizontal displacement or lateral displacement called, is a tectonic rejection , in which clods of earth's crust are slid past one another along a vertical surface. The mechanical tensions in the earth's crust, which are the cause of these movements, only rarely act completely parallel to a blade displacement, but mostly at an angle to the fault surface. In contrast to other faults, pure leaf displacements have no hanging or lying surface .

## Earthquake from leaf displacements

Because fault surfaces are irregular or curved, and the rock in the upper crust is very rigid and brittle, the friction on a fault surface is generally very high. Although the forces responsible for the movement act permanently, there is no continuous movement due to the strong friction. Instead, a “pressure” builds up on the disrupted surface, which is suddenly converted into movement when the counterforce generated by the friction is exceeded. Insofar as it is sufficiently violent, this movement is perceived by people as an earthquake .

## Sense of movement

Sense of movement at leaf shifts

Blade shifts can be divided into left ( sinistral e) and right-handed ( dextral e) shifts. To determine the sense of movement, the viewer will use the clod lying on the other side of the fault. If it has moved to the left, the disorder is left-handed (also left-sided, English left-lateral ), if it has moved to the right, then it is right-handed (also right-sided, English right-lateral ). It does not matter which of the two clods the viewer is standing on: a left-sided disturbance is left-sided from both perspectives, a right-sided one as well. The deletion of the fault area in relation to the cardinal points does not matter in this context.

## Examples

Satellite image of different colored Devonian and ancient Paleozoic sedimentary rocks of a tectonic blanket , which are offset by around 2 km at the Piqiang fault, a locally important left-handed (sinistral) leaf displacement, southern edge of the Tienschan in the far west of China.

Leaf shifts occur in all areas of the upper crust of the earth in which tectonic movements have subsequently overprinted the previous geology, which was determined by sedimentation or magmatism. The most extensive leaf displacements, which extend over several thousand kilometers, are found at the boundaries of the lithospheric plates , where they are referred to as transform faults . Well-known examples of such transform faults on the continents are the San Andreas Fault in California (USA) or the North Anatolian Fault in northern Turkey .

## literature

• Gerhard H. Eisbacher: Introduction to Tectonics . 1st edition. Ferdinand Enke Verlag, Stuttgart 1991, ISBN 3-432-99251-3 , pp. 69-81 .