| A | B |
|---|
| lithosphere | the solid rocky outer layer of the earth that includes the crust |
| plate tectonics | theory that states that the lithosphere is broken up into plates that move |
| fault | a crack in the earth's crust along which rock moves |
| focus | the point along a fault where rock first breaks or moves, causing an earthquake |
| seismograph | instrument that records the strengths of the earth's movements, based on the amount of energy released |
| Richter scale | a scale used to compare the strengths of an earthquake |
| plate | a huge slab of rock that includes the crust |
| convection current | a movement of matter where hot matter rises while cool matter sinks |
| mantle | the layer of the earth that lies between the crust and the core |
| magma | molten rock beneath the earths crust |
| fault boundary | an area where two plates are moving past each other |
| spreading boundary | an area where two plates are moving away from each other |
| colliding boundary | an area where two plates move toward each other |
| crust | the solid outer layer of the earth |
| lava | molten rock that flows from a volcano |
