Volcanoes can be described as openings in the Earth’s crust, through which molten rock, ash, and gases are emitted.
Volcanoes can be active or inactive.
Active volcanoes can be broadly divided into two main types:
Explosive volcanoes which give rise to large explosions which can partially destroy the volcano, project high columns of rock materials (rock debris, rock blocks, ash, steam, etc.) in the atmosphere and subsequently falling down along the sides of the volcano, as well as generating lava flows, mud and debris flows along the sides of the volcano, earthquakes and noxious gas emission.
Effusive Volcanoes which give to among other, slowly moving lava flows, little explosions, ground deformations, lava fountains, gas and steam emissions.
Prepared by CERG - European Centre on Geomorphological Hazards - Strasbourg, France & the Editorial Board