Geologic forces at work beneath the crust create mountains, rifts, and patterns of fractures, while the sluggish winds sculpt the surface in subtler ways.
Alpha Regio is an example of highly deformed crust called tessera. Such areas may be the oldest surfaces on Venus. They were produced by strong geologic forces that folded the crust and created interwoven patterns of ridges and valleys.
The Maxwell Montes, the bright area in this image, rise steeply from the smooth plateau to the west to heights of almost 11 kilometers (7 miles). The large, dark circular feature is the impact crater Cleopatra. High elevations typically appear very bright in radar images of Venus. This may be caused by a thin surface coating of metallic material that only forms above a certain altitude.
Width of image area: 1,265 km (786 mi.)
Winding across Venus are narrow belts where the surface has been pulled apart by geologic forces. Here such rifting has torn the crater Somerville in two. Usually less than a few hundred kilometers wide, rift zones contain dozens of nearly parallel ridges and valleys. Volcanoes often occur along these areas of weakened crust.
The tight pattern of bright and dark ripples in the center of this image is an area where loose material was sculpted by the gentle surface winds into dunes. The bright streaks of material curve away from small hills, revealing which way the winds were blowing. Stronger winds caused by meteorite impacts may also help create such features.
Width of image area: 172 km (107 mi.)
Unlike Earth, Venus shows no evidence of plate tectonics (the movement of large pieces of crust), a process that helps release interior heat. One way Venus releases heat is by the formation of a large number of features called coronae, circular patterns of fractures thought to form when hot material beneath the crust pushes up, warping the surface. Coronae are often accompanied by vast lava flows.
3D Perspective View of Idem-Kuva Corona on Venus
