Volcanic Formation and Eruptions

Volcano Formation

• Volcanoes form at constructive plate boundaries where tectonic plates move apart, creating a gap in the Earth's crust for magma to escape.
• At destructive plate margins, the heavier plate is pushed down into the Earth's mantle, melting into magma that rises to the surface.

Types of Volcanoes

• Composite volcanoes have steep sides due to thick, sticky lava that doesn't flow far before solidifying, leading to violent and explosive eruptions.
• Shield volcanoes have gentle, sloping sides due to thin, runny lava that flows far before solidifying, resulting in non-violent eruptions.
• Cinder cones are formed by small fragments of magma cooling quickly and falling as cinders, forming a crater around the volcano's summit.

Volcano Characteristics

• A volcano typically looks like a mountain or hill with a conical shape, featuring a main vent and often secondary vents.
• Lava from a volcano can reach temperatures of up to 1,250°C.

Volcano States

• Volcanoes are categorized according to their level of activity, with active, dormant, and extinct volcanoes.
• The 'Ring of Fire' contains 75% of the world's volcanoes, with 452 volcanoes stretching from South America to Japan and New Zealand.

Notable Volcanoes

• Mauna Loa in Hawaii is the world's largest active volcano, standing at 4,169m tall, and last erupted in 1984.
• Mount Vesuvius in Italy destroyed the town of Pompeii in A.D. 79.
• Mount St Helens in North America erupted in 1980 and 2008, with scientists predicting a future eruption.
• Mount Kilimanjaro in Africa is a dormant volcano.