A pyroclastic flow is a hot (typically >800 °C, or >1,500 °F ), chaotic mixture of rock fragments, gas, and ash that travels rapidly (tens of meters per second) away from a volcanic vent or collapsing flow front. Pyroclastic flows can be extremely destructive and deadly because of their high temperature and mobility.

A pyroclastic flow is a dense, fast-moving flow of solidified lava pieces, volcanic ash, and hot gases. It occurs as part of certain volcanic eruptions. A pyroclastic flow is extremely hot, burning anything in its path.

: formed by or involving fragmentation as a result of volcanic or igneous action.

A volcano is an opening in the earth’s crust through which lava, volcanic ash, and gases escape. Beneath a volcano, liquid magma containing dissolved gases rises through cracks in the Earth’s crust. As the magma rises, pressure decreases, allowing the gases to form bubbles.

A volcano is a landform, a mountain, where molten rocks erupt through the surface of the planet. The volcano mountain opens downwards to a pool of molten rocks underneath the surface of the earth. The volcano eruption can cause hot ash, lateral blasts and lava flow, mudslides, and more.

Volcanoes are classified as active, dormant, or extinct. Active volcanoes have a recent history of eruptions; they are likely to erupt again. Dormant volcanoes have not erupted for a very long time but may erupt at a future time. Some volcanic eruptions are explosive, while others occur as a slow lava flow.

There are three types of volcanoes: cinder cones (also called spatter cones), composite volcanoes (also called stratovolcanoes), and shield volcanoes.

There is no easy answer to this question, as scientists classify volcanoes in several different ways, including size, shape, explosivity, lava type, and tectonic occurrence. Furthermore, these different classifications often correlate.

Lesson Summary

• Composite, shield, cinder cones, and supervolcanoes are the main types of volcanoes.
• Composite volcanoes are tall, steep cones that produce explosive eruptions.
• Shield volcanoes form very large, gently sloped mounds from effusive eruptions.

Kilauea volcano

The top five biggest volcanic eruptions

• 5 – Mount Vesuvius. In Italy in AD 79, this volcano devastated the nearby cities of Pompeii and Herculaneum.
• 4 – Mount Ruiz.
• 3 – Mount Pelée.
• 2 – Mount Krakatoa.
• 1 – Mount Tambora.
• But the worst could still be to come…

Height of select volcanoes worldwide (in meters)

Tambora

Despite the fact that they’re active volcanoes, many are completely safe to visit, though you should always be aware of the risks associated with visiting a living, breathing volcano, which is essentially a vent for the hot gases and rocks located deep inside the Earth.

The most active volcanoes in the world Kilauea volcano on Hawaii is the world’s most active volcano, followed by Etna in Italy and Piton de la Fournaise on La Réunion island.

Indonesia