What You Need to Know

Key Concept Diagram

Earth's structure consists of a solid inner core, liquid outer core, mantle (including asthenosphere), and thin crust (oceanic and continental)

The lithosphere (crust + upper mantle) is broken into tectonic plates that move due to convection currents in the mantle

Convergent boundaries: plates collide (forming mountains or subduction zones); divergent boundaries: plates separate (forming rift valleys or mid-ocean ridges)

Transform boundaries: plates slide past each other horizontally, causing earthquakes (e.g., San Andreas Fault)

Key Vocabulary

Lithosphere

The rigid outer layer of Earth, consisting of the crust and the uppermost solid part of the mantle, broken into tectonic plates

Asthenosphere

The semi-fluid upper layer of the mantle beneath the lithosphere on which tectonic plates float and move

Subduction

The process by which a denser oceanic plate is forced beneath a lighter continental plate at a convergent boundary

Convection current

Circular movement of material driven by heat differences, which drives the movement of tectonic plates in the mantle

Knowledge Check

Select the correct answer for each question. Click "Check Answer" to see if you are right.

Question 1

At a convergent plate boundary where oceanic and continental plates meet, what typically occurs?

The oceanic plate subducts beneath the continental plate Plates slide horizontally past each other New seafloor is created Both plates move apart

Question 2

What drives the movement of tectonic plates?

The gravitational pull of the Moon Convection currents in the mantle The rotation of Earth on its axis Solar radiation heating the crust

Question 3

The Mid-Atlantic Ridge is forming where the North American and Eurasian plates are moving apart. What type of boundary is this?

Convergent boundary Transform boundary Divergent boundary Subduction zone

Tectonic Plates & Earth Structure