| A | B |
|---|
| Pangaea | supercontinent |
| Wegener | continental drift theory author |
| Glossopteris | fern fossil |
| Hess | sea floor spreading author |
| magnetic stripe | polarity reversal evidence |
| mid-ocean ridge | spreading center of rifts |
| oldest rocks | rock age near the continent |
| youngest rocks | rock age near the mid-ocean ridge |
| plate tectonics | continents move with lithosphere |
| continental drift | only continents move |
| asthenosphere | plastic-like layer below the lithosphere |
| mantle | earth layer below the crust |
| continental crust | least dense of the two crust types |
| oceanic crust | most dense of the two crust types |
| subduction | what happens when one plate dives under the other one |
| convergent | colliding plate boundary |
| divergent | separating type plate boundary |
| transform fault | laterally moving plate boundary |
| convection cells | circular mantle areas thought to move the plates |
| hot spots | areas of mid plate volcanoes |
| primary wave | first earthquake wave to arrive |
| secondary wave | earthquake wave one half of p wave's speed |
| Lwave | last wave to arrive |
| seismograph | measures earthquake waves |
| focus | actual place where earthquake occurs |
| epicenter | located on surface above focus |
| Tsunami | large seismic water wave |
| trench | deep troughs caused by subducting plates |
| Mt. St. Helens | Cascade volcano on a convergent boundary |
| island arc | volcanic string of volcanic islands caused by convergent boundary |
| iron and nickel | composition of Earth's core |
| magnetometer | device used to measure magnetism |
| iron | element in igneous rocks which indicates polarity |
| San Andreas Fault | transform fault created by the collision of the Pacific and N. American plates |
| Three | number of seismograph stations to determine an epicenter |
| rift valley | formation running through the center of the mid-ocean ridge |
| Hawaiian Is. & Yellowstone NP | sit on hot spots |
| earthquake | seismic wave caused by plate boundaries |
