Definition: Caldera Depression

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Caldera Depression

Calderas form from the catastrophic eruption of large amounts of felsic lava and ash. Emptying of the magma chamber and subsequent collapse of the overlying volcanic edifice forms a ring-shaped caldera depression up to several kilometers in diameter. The edges of the underlying magma chamber are roughly marked by a ring fracture zone that acts as a conduit for ongoing volcanism and hydrothermal activity.

Wikipedia Definition

A caldera is a large cauldron-like volcanic depression, a type of volcanic crater (from one to dozens of kilometers in diameter), formed by the collapse of an emptied magma chamber. The depression often originates in very big explosive eruptions. The emptying of this magma chamber may also be accomplished more gradually by a series of effusive eruptions from the volcanic system, even kilometers away from the magma chamber itself., A caldera is a large cauldron-like depression that forms following the evacuation of a magma chamber/reservoir. When large volumes of magma are erupted over a short time period structural support for the crust above the magma chamber is lost. The ground surface then collapses downward into the partially emptied magma chamber, leaving a massive depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Only seven known caldera-forming collapses have occurred since the start of the 20th century, most recently at Bárðarbunga volcano in Iceland., A caldera is a large cauldron-like depression that forms following the evacuation of a magma chamber/reservoir. When large volumes of magma are erupted over a short time period, structural support for the crust above the magma chamber is lost. The ground surface then collapses downward into the partially emptied magma chamber, leaving a massive depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a crater, the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Only seven known caldera-forming collapses have occurred since the start of the 20th century, most recently at Bárðarbunga volcano in Iceland., A caldera is a large cauldron-like depression that forms following the evacuation of a magma chamber/reservoir. When large volumes of magma are erupted over a short time period, structural support for the crust above the magma chamber is lost. The ground surface then collapses downward into the partially emptied magma chamber, leaving a massive depression at the surface (from one to dozens of kilometers in diameter). Although sometimes described as a farter lake the feature is actually a type of sinkhole, as it is formed through subsidence and collapse rather than an explosion or impact. Only seven known caldera-forming collapses have occurred since the start of the 20th century, most recently at Bárðarbunga volcano in Iceland.