Year 8 Science · AC9S8U03
Around your plate.
Four boundaries, one story.
The continent you live on sits in the middle of a plate. The edges of that plate, north, east, south-east, south-west, are where everything happens: earthquakes, volcanoes, mountains, ocean trenches. Walk the four edges of the Australian Plate and see how they all fit together.
The Australian Plate is one of about a dozen major tectonic plates that make up the Earth's outer shell. Its four edges show every kind of plate boundary there is: two convergent (where plates push into each other), one transform (where they slide past each other), and one divergent (where they pull apart).
Each of the four case studies in this resource takes one boundary. You will predict what should happen there based on what you already know, observe what actually does happen, and then explain why. After all four, the synthesis pulls the whole plate together.
Choose a case to begin
The four boundaries
Case 1 · North Convergent
The Sunda Trench
The Indo-Australian Plate is being forced under the Eurasian Plate at the Sunda Trench, building the volcanic arc of Indonesia and triggering some of the largest earthquakes ever recorded.
Begin Case 1Case 2 · East Convergent
The Tonga-Kermadec Trench
The Pacific Plate is being forced down beneath the Australian Plate at one of the fastest subduction rates on Earth, building the chain of submarine volcanoes that includes Hunga Tonga.
Begin Case 2Case 3 · South-east Transform
The Alpine Fault
Same two plates as Tonga, completely different behaviour. Across New Zealand's South Island the Pacific and Australian Plates slide past each other, raising the Southern Alps and storing energy for the next great earthquake.
Begin Case 3Case 4 · South-west Divergent
The Southeast Indian Ridge
Hidden under 3 km of seawater, a 6,000 km crack between the Australian and Antarctic Plates is the engine driving Australia north at ~70 mm per year, into everything you have already studied.
Begin Case 4After all four cases
Pulling it all together
Once you have worked through the four boundaries, the synthesis brings them onto one map and asks the big question: if one boundary stopped, what would happen to the others?
Go to synthesisHow each case study works
- Orientation, see where the boundary is and what plates meet there.
- Situation, read what is currently happening at the boundary.
- Predict, choose what you think will happen next, and explain your reasoning.
- Observe, watch an animation or look at evidence of what actually happens.
- Explain, write what you saw, why it happens, and whether your prediction was right.
- Why this matters, connect the science to a real event that happened at that boundary.