Volcanoes and Volcanology

• The Earth's crust is a thin shell that covers 1% of the Earth's volume, and it is where volcanoes are found.
• Volcanoes come in different shapes and sizes, depending on the amount of pressure in the magma chamber and the difficulty in breaking through the surface.
• There are four main types of volcanoes: cinder cones, composite volcanoes, shield volcanoes, and lava domes.
• Cinder cones are simplest, built from congealed lava ejected from a single vent, and have violent eruptions.
• Composite volcanoes are steep-sided, symmetrical cones built with layers of lava flows and cinders, and have a crater at the summit.
• Shield volcanoes have a flatter, rounded shape and are built from slow, thin layers of fluid lava.
• Lava domes are smaller, with lava too thick to flow far, and they expand from inside to out as the lava cools and hardens.
• Magma is made mostly of aluminum, calcium, iron, magnesium, oxygen, potassium, silicon, sodium, and titanium.
• Volcanic activity can include hot gas, lava, or perfectly still, steady flows.
• Volcanic activity happens for various reasons, including instability due to shifting tectonic plates or magma chambers.
• An eruption is a sudden discharge of volcanic material, which can be unexpected and violent.
• Effusive eruptions are less violent and contain more liquid magma, while explosive eruptions are much more violent and spew thicker magma and rocks into the air.
• Hazards of volcanic eruptions include gas clouds, acid rain, tephra ash, lava flow, landslides, pyroclastic flows, tsunamis, earthquakes, and loss of plants and habitats.
• Iceland, which sits between two continental plates, is expanding every year and has more than 130 volcanoes.

Test your knowledge about volcanoes and volcanology with this quiz. Learn about the formation of volcanoes, their characteristics, and where they are found in our solar system.