| A | B |
|---|
| Pangaea | the single landmass that existed more than 200 million years ago.This gave rise to the present-day continents |
| Fault | a break or crack along which rocks move |
| Ring of Fire | the earthquake and volcano zone that encircles the Pacific Ocean |
| mantle | the layer of the the Earth that extends from the bottom of the crustto the core |
| convergent boundaries | a plate boundary at which plates come together |
| divergent boundaries | a plate boundary at which move apart |
| magma | molten rock beneath the Earth's surface |
| trench | a V-shapedvalley on the ocean floor where the old ocean floor is subducted |
| seismograph | an instrument that detects and measures seismic waves |
| Richter Scale | the scale used to measure the strength of earthquakes |
