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Global Volcanoes

Volcanoes Data Criteria
With few exceptions, we have used the names listed by the compilers of the Catalog of Active Volcanoes of the World (CAVW), the contributors to the International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) post-Miocene data sheets, and individual volcanologists reporting on additional volcanoes. In the case of volcanoes that comprise islands, we have preferred broader island names, locatable on standard maps, rather than crater names locally used to identify the full island volcano, and we have dropped modifiers, such as "Mount," when they seemed unnecessary.[Read more]
Eruption Data Criteria
Any attempt to assess the distribution of volcanism through time must take into account the variable definitions of the word eruption. We consider an eruption to consist of the arrival of solid volcanic products at the Earth's surface. This can be in the form of either the explosive ejection of fragmental material or the effusion of initially liquid lava. This definition excludes energetic, but non-ash-bearing steam eruptions. The ejection of fragmental material, however, does not require magmatic explosions producing fresh (juvenile) pyroclastics; phreatic explosions of greatly variable intensity are produced by the interaction of volcanically generated heat and near-surface water and can eject significant amounts of old material.[Read more]
Types Of Volcano
Stratovolcanoes (also known as composite volcanoes) are what most people associate with the word volcano. These towering peaks rise hundreds to several thousand meters above their surroundings, often visually dominating the landscape around them. As their name implies, they are formed of stratified layers of both viscous lava flows and fragmental material. Classic symmetrical stratovolcanoes such as Shishaldin in the Aleutian Islands and Mayon in the Philippines are the exception rather than the rule. [Read more]

Volcanic Processes
The interaction of magma with water near Earth's surface can intensify explosive eruptions. Steam-driven explosive eruptions, known as phreatic eruptions, can occur when an ascending magma body encounters groundwater. The ensuing eruptions often do not involve any ejection of new magma, but rather the fragmentation and explosive expulsion of pre-existing rock along the path of the volcanic conduit.
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