A circular depression on the earths surface caused by volcanic activity.
Classically found at the summit of a volcano craters can also be found on the flanks of volcanoes. A crater will have a vent which is connected to a magma chamber from which lava can erupt. Hydrothermal activity in the form of fumaroles is common. Crater lakes may also form which may be highly acidic and hot ie. White island New Zealand. Should the magma chamber become evacuated rapidly during an eruption the it may collapse to form a caldera. Some volcanoes have multiple craters on the summit area such as Mt.Etna.