Volcanoes are openings, or vents where lava, tephra (small rocks), and steam erupt onto the Earth's surface. Volcanic eruptions can last days, months, or even years. What is a volcano? Redoubt volcano with minor ash eruption. Photograph taken during observation and gas data collection flight by AVO staff March 30, 2009.

There are more than 1,500 potentially active volcanoes or volcanic areas around the world at any given time. They may be the world’s most dynamic landforms, given their ability to grow by accretion or shatter and collapse during an eruption.

2025年2月4日 · volcano, vent in the crust of Earth or another planet or satellite, from which issue eruptions of molten rock, hot rock fragments, and hot gases. A volcanic eruption is an awesome display of Earth’s power.

Volcanoes, based on their frequency of eruption or volcanism, can be defined as either active, dormant or extinct. Active volcanoes have a recent history of volcanism and are likely to erupt again, dormant ones have not erupted in a long time but may erupt later, while extinct ones are not capable of eruption at all.

2018年1月15日 · Volcanoes are Earth's geologic architects. They've created more than 80 percent of our planet's surface, laying the foundation that has allowed life to thrive. Their explosive force crafts...

2025年1月14日 · Volcanoes occur when material significantly warmer than its surroundings is erupted onto the surface of a planet or moon from its interior. On Earth, the erupted material can be liquid rock ("lava" when it's on the surface, "magma" …

The most well-known types of volcanoes are cinder cones, composite volcanoes (stratovolcanoes), and shield volcanoes. The illustration below provides an example of the difference in size between shield, composite, and cinder cone volcanoes.