Volcano
A volcano is an an opening in a planet's surface, usually mountainous, which allows hot, molten rock, ash and gases to escape from below the surface.
Volcanos on Earth
In 79, the Roman city of Pompeii was destroyed in a volcanic eruption. (BFA: The Fires of Vulcan)
In 1883, the Doctor witnessed the eruption of the volcano Krakatoa. (DW: Inferno)
In the 21st century, Salamander triggered volcanic eruptions in Hungary as part of his plan to take control of Earth. (DW: The Enemy of the World)
In 2167, the Daleks' attempt to mine Earth's core instead resulted in a volcanic eruption in Bedfordshire. (DW: The Dalek Invasion of Earth)
Volcanos on Other Worlds
On Dulkis, the Dominators' attempt to turn the planet into starship fuel instead resulted in a volcanic eruption that threatened the Doctor's TARDIS. (DW: The Dominators)
Planets with high levels of volcanic activity included the following: