Plate tectonics: boundaries, earthquakes and volcanoes
Learn how Earth's plates move, the three types of plate boundary and why earthquakes and volcanoes happen, with real examples.
KS3GCSEMiddle SchoolHigh SchoolCurriculum fit: KS3 and GCSE Geography (tectonic hazards); US middle and high school Earth science (Earth's systems: plate tectonics).
On this page
What is it?
Earth's outer layer, the lithosphere, is broken into large pieces called tectonic plates. They move slowly, typically a few centimetres a year, on the softer layer beneath. Most earthquakes and volcanoes occur where plates meet.
The way plates move relative to each other creates different kinds of boundary and different landforms and hazards.
Key formulas and ideas
- Divergent boundary: plates move apart and new crust forms (such as the Mid-Atlantic Ridge).
- Convergent boundary: plates move together. Subduction creates volcanoes and trenches; continental collision creates fold mountains (such as the Himalayas).
- Transform boundary: plates slide past each other (such as the San Andreas Fault in California).
- The Pacific 'Ring of Fire' is a belt of volcanoes and earthquakes around the Pacific Ocean.
Worked examples
Example 1: Name the boundary
Question: Identify the type of boundary at the San Andreas Fault and describe the hazard.
- Two plates slide past each other.
- Friction builds up stress, which is released as earthquakes.
Answer: A transform boundary, with earthquake hazard
Example 2: How mountains form
Question: Explain how the Himalayas were formed.
- The Indian plate moved north and collided with the Eurasian plate.
- Neither plate was subducted easily, so the crust was crumpled and folded upwards.
Answer: Continental collision created fold mountains
Example 3: Why is Japan at risk?
Question: Why does Japan experience frequent earthquakes and volcanoes?
- It lies in the Ring of Fire, on plate boundaries.
- Oceanic plates subduct beneath it, causing earthquakes and volcanoes.
Answer: It is on convergent plate boundaries in the Ring of Fire
Common mistakes
- Saying that the continents float on the sea. They are part of plates on the mantle.
- Mixing up divergent and convergent boundaries.
- Saying earthquakes can be predicted exactly.
- Forgetting that volcanoes can also form away from plate boundaries, at hotspots.
Practice questions
Frequently asked questions
Can we predict earthquakes?
Scientists can map where earthquakes are likely, but cannot predict the exact time and place of one.
Can scientists predict earthquakes?
They can map where earthquakes are likely, but cannot predict exactly when and where one will happen.
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GCSEA-LevelHigh SchoolAPSources and review
- DfE: National curriculum in England, geography programmes of study (key stages 1 to 3)
- Next Generation Science Standards: search the standards
Reviewed by StudyMorrow editorial review on 5 Nov 2026.