| A | B |
|---|
| crust | Earth's outer layer |
| mantle | The thickest layer of Earth - below the crust |
| core | The dense center of the Earth |
| plates | Continent-sized slab of Earth's crust and upper mantle |
| earthquake | A vibration, or shaking, of Earth's crust |
| fault | A break in Earth's crust along which rocks move |
| focus | The point underground where the movement of an earthquake first takes place |
| epicenter | The point on the surface of Earth that is right above the focus of an earthquake |
| seismograph | An instrument that records earthquake waves |
| volcano | A mountain that forms when red-hot melted rock flows through a crack onto Earth's surface |
| magma | Melted rock inside Earth |
| lava | Melted rock that reaches Earth's surface |
| vent | In a volcano, the rocky opening through which magma rises toward the surface |
| magma chamber | An underground pool that holds magma, below a volcano |
| crater | A large basin formed at the top of a volcano when the top falls in on itself |
