Plate Boundaries
Geography: Cambridge International GCSE (2027 Exams), topic 4.1.4
Hotspots and Volcanoes at Plate Bondaries
A volcano is an opening in the Earth's crust that is formed when magma rises from inside the earth and erupts onto the surface. Volcanoes can be formed at constructive and destructive plate margins.
Destructive plate margins
- The denser oceanic plate is forced under the continental plate at destructive margins.
- The friction and pressure cause cracks (vents) to form in the continental plate. The magma rises up through these cracks.
- This usually creates highly explosive volcanoes (e.g. Mount Vesuvius in Italy) that produce a lot of gas and lava (magma above the surface).
Constructive plate margins
- At constructive plate margins, the plates move apart (diverge).
- The convection currents in the mantle diverge (move apart) and cause a gap between the plates.
- Magma rises up to fill this gap with a volcano.
- This kind of volcano is common in Iceland.
Hotspots
- At hotspots, there is a hot mass of rising heat under a weakness in a plate.
- Magma rises to the surface through this weakness.
- The Hawaiian islands all formed as a result of a mid-Pacific hotspot.
Test yourself on Plate Boundaries
What do we call an opening in the Earth's crust?
Volcano Formation at Destructive Plate Margins