Tallon IV may have volcanic activity due to the magma in Magmoor Caverns even though no volcano is actually seen. However, while most of the area is located underground, there are a few rooms where the ceiling is opened to the sky; this points to the fact that there are breaches on the surface of the planet, in other words, volcanoes, and that the mentioned rooms are actually volcanic craters.
The planet Alinos is nicknamed "Volcanic Ruin" in its scan due to the destruction of its core. Alinos is evident to have volcanic activity though no volcanoes are shown. However, there are pillar-like rocks that look remarkably similar to volcanoes, but lava is never shown to be spurting out of them.
Just like Alinos, volcanoes are not shown but evident. The presence of a volcano is noticeable while exploring Crateria, the surface area of Zebes: the same super-heated lava seen deep below underground in Ridley's Lair is also present in Crateria, no doubt having reached the latter area through an opening or breach created by diverging or converging of tectonic plates.
A volcano appears in Pyrosphere in Metroid: Other M. The volcano is seen erupting in the far background of a long pathway, spewing chunks of rock at Samus which she is required to constantly dodge; these rocks contain Sovas. She ultimately stops the flow of the volcano after defeating Goyagma in the volcano's interior. However, due to the fact that the Pyrosphere is inside a space station, the volcano is likely artificial and its volcanic activity simulated to produce an adequate environment to contain heat-based lifeforms.
Pyroclasm in the PyrosphereEdit
"The Pyrosphere, a simulated volcanic area encompassing Sector 3, was predictably awash in magma flows, lava pools, and a host of beasts adapted to extreme heat. Nonetheless, finding an erupting volcano caught me off-guard, especially when it began raining chunks of flaming rock on me. The Varia feature of my suit quickly became necessary."
- In Metroid: Zero Mission, pools of lava exist in the Chozodia temple, which is part of, or quite near, the surface area of Zebes. Whether this lava was brought into the temple through the actions of the Chozo, or if the temple was built near a volcano is unknown.
- SR388 is suggested to have volcanoes, due to high levels of acid blocking off parts of the planet, which for unknown reasons sinks after all Metroids in one area have been eradicated.
- The name "Volcano Island" was seen on a computer monitor in footage of the Metroid.jp interview. It is unknown if this referred to Pyrosphere or another area.
- In the room where Samus is authorized to use her Ice Beam, chunks of rocks are flung onto the floor as the Mellas begin to spawn from the Fly Pod. It is unknown if the volcano was erupting and launching these.
- The volcano can also be seen in the distance from a room containing a glass tube half-eaten by Vorash, but it is inactive and does not do anything.
- Liberty has an inactive volcano, named Mount Pagos.
- Another inactive volcano appears on the ocean world, on the bottom of the sea floor. Samus triggers it to save herself, Joey and Diesel from the sulfuric acid ocean and kill those responsible, Defen and Rastodon.