Strictly, volcanic activity beneath ice sheets or glaciers, but used generally to refer to volcanic eruptions where magma interacts with ice in any form, both on Earth and other planetary bodies (Glaciovolcanism). Subglacial volcanism may occur wherever volcanic vents are covered in bodies of ice, which may include small glaciers on the flanks of stratovolcanoes, substantial regional ice sheets and even the Martian cryosphere (Smellie, 2000, see “Ice-volcano interactions”).