Volcano Definition and Types

Study Notes

A volcano is an opening in a planet's crust where molten rock, ash, and gases are expelled from below.
Mount Rinjani on Lombok is Indonesia’s second highest active volcano.
Active Volcanoes erupt within the last 10,000 years and have documented eruptions.
Extinct Volcanoes have no eruptions in historical times and are unlikely to erupt again due to depleted magma supply.
Dormant Volcanoes are also known as inactive volcanoes.

Composite Volcanoes (Stratovolcanoes) are characterized by tall peaks with craters, releasing pyroclastic materials, gases, and lava. They are the most common type.
Silica in lava increases its viscosity, allowing it to reach significant heights.
Shield Volcanoes have broad, gentle slopes resembling a warrior’s shield, with lower silica percentages making the lava less viscous. Example: Mauna Loa in Hawaii.
Cinder Cones (Pyroclastic Cones) are typically small and composed of pyroclasts, often forming groups around larger volcanoes, with most eruptions occurring only once.
Submarine Volcanoes are easier to detect in shallow waters.

Pyroclasts are fragments of volcanic rock that create steep slopes surrounding wide craters.
Paricutin is a notable cinder cone located in Mexico.
Hydrophones are devices invented in Britain for detecting underwater volcanic sounds.
Subglacial Volcanoes are found in high-latitude regions, such as Iceland.

The International Association of Volcanology and Chemistry of the Earth's Interior (IAVCEI) is an organization focused on volcanic research.
Decade Volcanoes are distinguished by their history of destructive eruptions and proximity to populated areas.