The document discusses rift valleys on Venus and Earth. It notes that the largest rift valley on Earth is the East African Rift, and provides an image showing a rift valley on Venus near Gula Mons and Sif Mons. While rift valleys on Earth are caused by the movement of tectonic plates, the large rift valleys on Venus are thought to be due to more local tectonic activity, as the surface of Venus appears to consist of a single plate.

1. Rift valley

2. Rift Valleys
There are rift valleys as large as the East African Rift (the largest on Earth). The image shown
below illustrates a rift valley in the West Eistla Region, near Gula Mons and Sif Mons.
Rift valley on Venus

3. The perspective in cases like this is synthesized from radar data taken from different positions
in orbit.
The East African Rift on Earth is a consequence of tectonic motion between the African and
Eurasian plates (the Dead Sea in Israel is also a consequence of this same plate motion). Large
rift valleys on Venus appear to be a consequence of more local tectonic activity, since the
surface of Venus still appears to be a single plate.