Volcano Formation and Activity

Volcano Formation

• Magma, hot molten rock, collects in a chamber beneath the Earth's surface.
• Pressure builds, causing magma to erupt from a vent (opening or crack).
• Eruptions form volcanoes.
• Eruptions can be quiet (gentle lava flow) or explosive (violent lava flow).
• Erupted material, including rocks, ash, and lava, cools to form volcanic rock.
• The crater is the bowl-shaped hollow at the top of the volcano.
• Volcanic eruptions can sometimes be accompanied by earthquakes.

Types of Volcanic Activity

• Quiet eruptions involve gentle lava flow.
• Explosive eruptions involve violent lava flow.

Other Natural Disasters

• Extinct volcanoes are inactive after years.
• Tsunamis, a series of enormous waves, can be triggered by volcanic eruptions or landslides.
• Other natural disasters (besides earthquakes and Tsunamis) are discussed later in the text.