A spreading apart of the surface causes tensional forces.

Around 18 million years ago, tensional forces started to thin and drop the region to the west, creating the Basin and Range province.

Once tensional forces cease, subsidence continues due to cooling.

Horst and graben structures are indicative of tensional forces and crustal stretching.

This area and its antipode in the Discovery quadrangle are the only two on Mercury where tensional forces can now be seen to have shaped the surface.

Graben or rift valley: down dropped and typically linear depressions or basin created by rifting in a region under tensional tectonic forces.

This fault pattern is caused by the tensional forces pulling apart the adjacent Basin and Range province to the west, making this section transitional.

Grabens are indicative of tensional forces and crustal stretching.

Fault-block mountains often result from rifting, another indicator of tensional tectonic forces.

They occur in areas where the Earth's crust is subjected to tensional forces, trying to pull it apart.