Przesuw

Przesuw is a geological term describing horizontal movement of rock masses along a fault plane, caused by tectonic forces within the Earth's lithosphere. The slip results from accumulated stress that causes blocks of crust to move past one another along the fault. When the motion is predominantly horizontal, it is commonly described as strike-slip displacement; when there is also a vertical component, the motion is termed oblique-slip.

Surface evidence of przesuw includes linear fault traces, offset streams and roads, sag ponds, and linear topographic features. Subsurface slip is inferred from seismic activity and fault-plane focal mechanisms. The rate of przesuw—how fast the blocks slide past each other—varies widely, from less than a millimeter to several centimeters per year, depending on tectonic setting and local rock properties.

Studying przesuw employs seismology, geodetic techniques such as GPS and InSAR, and paleoseismology to reconstruct past earthquakes and slip rates. In global tectonics, strike-slip faults accommodate horizontal motion between tectonic plates at transform boundaries; oblique-slip faults include a vertical component and can generate complex rupture patterns.

Polish geology uses the term przesuw to describe this type of fault motion. The English equivalents are "slip" or "slip along a fault" and the specific forms include strike-slip (lateral) faults and oblique-slip faults.