| A | B |
|---|
| molten rock (at the surface) | lava |
| molten rock (deep within the Earth) | magma |
| lithospheric plate | top most solid part of the Earth |
| convergent boundry | a plate boundry at which plates come together |
| divergant boundry | a plate boundry at which plates move apat |
| Pangea | the single giant landmass that existed over 200 million years ago |
| ocean floor spreading | the process in which old ocean floor is pushed away from a midocean ridge by the formation of new ocen floor |
| convection currents | a movement of material caused by differences in currents |
| seismograph | an instument that detects and measures seismic waves |
| Ring of Fire | the earthquake and volcanic zone that encircles the Pacific Ocean |
| Richter Scale | the scale used to measure the strengh and occurancy of earthquakes |
