Geothermal and Hydrothermal Features

This group collects the Volcanic Formations subcategory's members whose own description identifies them as a geothermal or hydrothermal feature, a hot spring, fumarole or geyser field powered by heat still rising from magma at depth rather than by an active eruption or a standing volcanic edifice of their own. These four members are kept apart from the subcategory's constructive and explosive volcano-type groups because their defining feature is the ongoing heat and fluid activity itself, not a landform built or excavated by an eruption.