Plate Tectonics
Introduced| English |
|---|
| plate tectonics/pleɪt tekˈtɒnɪks/ |
| tectonic plate/tekˈtɒnɪk pleɪt/ |
| convergent/kənˈvɜːdʒənt/ |
| divergent/daɪˈvɜːdʒənt/ |
| transform/trænsˈfɔːm/ |
The moving Earth
- The ground feels solid and still, but it is slowly moving.
- Earth's outer shell is cracked into giant pieces.
- These pieces drift over the hot, soft layer beneath.
- Their slow motion shapes mountains, oceans, and earthquakes.
Plates on the move
- Plate tectonics 板块构造 is the idea that Earth's shell is broken into moving plates.
- Each tectonic plate 构造板块 carries continents and ocean floor.
- They move only centimetres a year — about as fast as your nails grow.
- Where their edges meet, dramatic things happen.
Plate tectonics is the idea that…
Plate tectonics: Earth's rigid outer shell is broken into tectonic plates that slowly move.
Three kinds of boundary
- At a convergent 汇聚型 boundary, plates push together — raising mountains or deep trenches.
- At a divergent 离散型 boundary, plates pull apart, and new crust forms in the gap.
- At a transform 转换 boundary, plates slide past each other.
- The type of boundary decides what landforms and hazards appear.
At a convergent boundary, plates…
At a convergent boundary plates collide, raising mountains or forming deep trenches.
Where plates move apart and new crust forms, the boundary is called ____.
At a divergent boundary plates pull apart, and new crust rises to fill the gap.
Boundaries and hazards
- Most earthquakes and volcanoes happen along plate boundaries.
- As plates grind past or under one another, stress builds and releases as quakes.
- Melting rock rises at boundaries to form volcanoes.
- This is why some regions face far more geologic hazards than others.
What kind of boundary?
Sort each event by the type of plate boundary that causes it - plates moving apart, together, or sliding past.
Earthquakes and volcanoes are common along plate boundaries.
The grinding of plates at their boundaries causes most earthquakes and volcanoes.
Select all true statements about plate tectonics.
Boundaries are where earthquakes and volcanoes cluster, not calm. The other three are correct.
Earthquakes and volcanoes are not random — they cluster along plate boundaries. The "Ring of Fire" around the Pacific is a chain of convergent boundaries, which is why that region has so many of the world's earthquakes and volcanoes.
The Himalayas, still rising:
- The plate carrying India is pushing north into the plate carrying Asia.
- This convergent boundary crumples the crust upward.
- The collision built the Himalayas — and the mountains are still slowly rising today.
Plate tectonics is the theory that Earth's shell is broken into moving tectonic plates. Their boundaries come in three kinds: convergent (colliding, building mountains and trenches), divergent (spreading, making new crust), and transform (sliding past). Most earthquakes and volcanoes occur along these boundaries.