Volcanoes and Eruptions

Volcano Formation

• The two important layers of the Earth for volcano formation are the mantle and the crust.

Volcano Eruption

• A volcano erupts when magma rises through cracks and spills out onto the Earth's surface as lava.

Volcano Formation Process

• A volcano is formed when magma from the Earth's interior rises through cracks in the Earth's crust, solidifies, and accumulates, resulting in a volcanic cone.

Volcano Structure

• A volcano has several key parts, including the vent (where ash, gas, and lava escape), magma chamber (where magma accumulates), crater (the depression at the top of the volcano), and cone (the outer shape of the volcano).

Types of Volcanoes

• There are three types of volcanoes: composite, shield, and cinder cone.
• Composite volcanoes are tall and conical, and typically have violent eruptions.
• Shield volcanoes are gently sloping and typically have non-violent eruptions.

Volcano Characteristics

• Lava from a volcano can reach temperatures of up to 3210°C.
• Magma can increase the pressure in the magma chamber, leading to a volcanic eruption.
• The vent is where ash, gas, and lava escape from the volcano during an eruption.

Plate Tectonics

• Destructive plate boundaries are where one plate is being subducted (pushed) under another plate, resulting in volcanic activity.
• Constructive plate boundaries are where two plates are moving apart, resulting in volcanic activity.

Volcanic Hotspots

• Hawaii is an example of a volcanic hotspot, where magma rises from the Earth's mantle to the surface, creating a chain of volcanoes.

True or False

• When volcanoes erupt violently, this can cause the top of the volcano to blow out. (True)
• Composite volcanoes do not have steep sides and usually have violent eruptions. (False, composite volcanoes have steep sides and violent eruptions)
• Shield volcanoes are steep and violent. (False, shield volcanoes are gently sloping and typically have non-violent eruptions)

Multiple Choice

• An extinct volcano is Ben Nevis in Scotland.