Triton is geologically active; its surface is young and has relatively few impact craters.
 Although Triton's crust is made of various ices, its subsurface processes are similar to those that produce volcanoes and rift valleys on Earth, but with water and ammonia as opposed to liquid rock.
Triton's entire surface is cut by complex valleys and ridges, probably the result of tectonics and icy volcanism.
The vast majority of surface features on Triton are endogenic—the result of internal geological processes rather than external processes such as impacts.
Most are volcanic and extrusive in nature, rather than tectonic.

One of the largest cryovolcanic features found on Triton is Leviathan Patera, a caldera-like feature roughly 100 km in diameter seen near the equator.
Surrounding this caldera is a volcanic dome that stretches for roughly 2000 km along its longest axis, indicating that Leviathan is the second largest volcano in the solar system by area, after Alba Mons.
This feature is also connected to two enormous cryolava lakes seen northwest of the caldera.
Because the cryolava on Triton is believed to be primarily water ice with some ammonia, these lakes would qualify as stable bodies of surface liquid water while they were molten.
This is the first place such bodies have been found apart from Earth, and Triton is the only icy body known to feature cryolava lakes, although similar cryomagmatic extrusions can be seen on Ariel, Ganymede, Charon, and Titan.

The Voyager 2 probe observed in 1989 a handful of geyser-like eruptions of nitrogen gas and entrained dust from beneath the surface of Triton in plumes up to 8 km high.
Triton is thus, along with Earth, Io, Europa and Enceladus, one of the few bodies in the Solar System on which active eruptions of some sort have been observed.
The best-observed examples are named Hili and Mahilani (after a Zulu water sprite and a Tongan sea spirit, respectively).

All the geysers observed were located between 50° and 57°S, the part of Triton's surface close to the subsolar point.
This indicates that solar heating, although very weak at Triton's great distance from the Sun, plays a crucial role.
It is thought that the surface of Triton probably consists of a translucent layer of frozen nitrogen overlying a darker substrate, which creates a kind of "solid greenhouse effect".
Solar radiation passes through the thin surface ice sheet, slowly heating and vaporizing subsurface nitrogen until enough gas pressure accumulates for it to erupt through the crust.
A temperature increase of just 4 K above the ambient surface temperature of 37 K could drive eruptions to the heights observed.
Although commonly termed "cryovolcanic", this nitrogen plume activity is distinct from Triton's larger scale cryovolcanic eruptions, as well as volcanic processes on other worlds, which are powered by internal heat.
CO₂ geysers on Mars are thought to erupt from its south polar cap each spring in the same way as Triton's geysers.

Each eruption of a Triton geyser may last up to a year, driven by the sublimation of about 100 million cubic metres (3.5×10⁹ cu ft) of nitrogen ice over this interval; dust entrained may be deposited up to 150 km downwind in visible streaks, and perhaps much farther in more diffuse deposits.
Voyager 2's images of Triton's southern hemisphere show many such streaks of dark material.
Between 1977 and the Voyager 2 flyby in 1989, Triton shifted from a reddish colour, similar to Pluto, to a far paler hue, suggesting that lighter nitrogen frosts had covered older reddish material.
The eruption of volatiles from Triton's equator and their deposition at the poles may redistribute enough mass over the course of 10,000 years to cause polar wander.
Triton is geologically active; its surface is young and has relatively few impact craters.  Although Triton's crust is made of various ices, its subsurface processes are similar to those that produce volcanoes and rift valleys on Earth, but with water and ammonia as opposed to liquid rock. Triton's entire surface is cut by complex valleys and ridges, probably the result of tectonics and icy volcanism. The vast majority of surface features on Triton are endogenic—the result of internal geological processes rather than external processes such as impacts. Most are volcanic and extrusive in nature, rather than tectonic.
One of the largest cryovolcanic features found on Triton is Leviathan Patera, a caldera-like feature roughly 100 km in diameter seen near the equator. Surrounding this caldera is a volcanic dome that stretches for roughly 2000 km along its longest axis, indicating that Leviathan is the second largest volcano in the solar system by area, after Alba Mons. This feature is also connected to two enormous cryolava lakes seen northwest of the caldera. Because the cryolava on Triton is believed to be primarily water ice with some ammonia, these lakes would qualify as stable bodies of surface liquid water while they were molten. This is the first place such bodies have been found apart from Earth, and Triton is the only icy body known to feature cryolava lakes, although similar cryomagmatic extrusions can be seen on Ariel, Ganymede, Charon, and Titan.
The Voyager 2 probe observed in 1989 a handful of geyser-like eruptions of nitrogen gas and entrained dust from beneath the surface of Triton in plumes up to 8 km high. Triton is thus, along with Earth, Io, Europa and Enceladus, one of the few bodies in the Solar System on which active eruptions of some sort have been observed. The best-observed examples are named Hili and Mahilani (after a Zulu water sprite and a Tongan sea spirit, respectively).
All the geysers observed were located between 50° and 57°S, the part of Triton's surface close to the subsolar point. This indicates that solar heating, although very weak at Triton's great distance from the Sun, plays a crucial role. It is thought that the surface of Triton probably consists of a translucent layer of frozen nitrogen overlying a darker substrate, which creates a kind of "solid greenhouse effect". Solar radiation passes through the thin surface ice sheet, slowly heating and vaporizing subsurface nitrogen until enough gas pressure accumulates for it to erupt through the crust. A temperature increase of just 4 K above the ambient surface temperature of 37 K could drive eruptions to the heights observed. Although commonly termed "cryovolcanic", this nitrogen plume activity is distinct from Triton's larger scale cryovolcanic eruptions, as well as volcanic processes on other worlds, which are powered by internal heat. CO₂ geysers on Mars are thought to erupt from its south polar cap each spring in the same way as Triton's geysers.
Each eruption of a Triton geyser may last up to a year, driven by the sublimation of about 100 million cubic metres (3.5×10⁹ cu ft) of nitrogen ice over this interval; dust entrained may be deposited up to 150 km downwind in visible streaks, and perhaps much farther in more diffuse deposits. Voyager 2's images of Triton's southern hemisphere show many such streaks of dark material. Between 1977 and the Voyager 2 flyby in 1989, Triton shifted from a reddish colour, similar to Pluto, to a far paler hue, suggesting that lighter nitrogen frosts had covered older reddish material. The eruption of volatiles from Triton's equator and their deposition at the poles may redistribute enough mass over the course of 10,000 years to cause polar wander.
Triton (moon)