Plate Tectonics
Earth's lithosphere is split into plates that move slowly.
About this topic
Earth's lithosphere is broken into about 15 major plates that move a few centimetres per year, driven by mantle convection, slab pull and ridge push. Plate tectonics explains the distribution of continents, mountains, earthquakes, volcanoes and ocean basins.
Evidence includes the fit of continents, matching fossils and rocks across oceans, magnetic stripes on the sea floor and the pattern of earthquakes and volcanoes. The theory unified geology in the 1960s, building on Wegener's continental drift.
Plate speeds are about the same as the rate your fingernails grow, around 2 to 10 cm a year, yet over 100 million years that adds up to thousands of kilometres. India collided with Asia after moving north at up to 15 cm a year, building the Himalayas, which still rise by a few millimetres each year. GPS stations now measure plate movement directly.
Slab pull, where the cold dense edge of a plate sinks into the mantle and drags the rest along, is thought to be the strongest driver. Ridge push comes from the elevated ridge sliding downhill, and mantle convection currents provide the underlying heat engine. Magnetic stripes form because new rock at ridges records Earth's magnetic field direction as it cools, and the field has reversed many times, giving a symmetrical zebra pattern on either side. Plate tectonics matters for predicting hazards, finding ores and oil, and explaining why life diversified. A common misconception is that continents plough through the ocean floor; instead continents ride along with the plates.
Key ideas
- Plates ride on the asthenosphere
- Move a few cm per year
- Cause earthquakes and mountains
Quick check
Use cases: where Plate Tectonics helps
- Homework: review the key idea behind Plate Tectonics before you start a problem set.
- Exam revision: use the quick check to test whether you can recall Plate Tectonics without notes.
- Visual learning: play with the interactive lab to see how Plate Tectonics changes when you adjust its inputs.
- Teaching a friend: explain Plate Tectonics in your own words, then compare your version with the key ideas.
Earth science helps with weather forecasts, natural hazards, energy and climate planning.
Frequently asked questions
What is Plate Tectonics?
Earth's lithosphere is split into plates that move slowly.
What will I learn in Plate Tectonics?
Plates ride on the asthenosphere. Move a few cm per year. Cause earthquakes and mountains.
Is Plate Tectonics part of Earth & Space?
Yes. It is one of 60 Earth & Space topics on LearnViz HighSchoolEdu, with 3 key ideas, a live animation and a quick check.
Does the Plate Tectonics lab work on a phone or tablet?
Yes. The animation resizes to fit your screen and supports touch, so you can drag, tap and slide with your finger.
How should I study Plate Tectonics?
Read the summary and key ideas first, play with the interactive lab to see the idea in motion, then answer the quick check. If you get a question wrong, go back to the key idea it tests.
Do I need an account, and is my progress saved?
No account is needed. Marking a topic as learned is saved in your own browser, so it stays on that device and is not sent to a server.