| A | B |
|---|
| asthenosphere | partially melted layer of the mantle that underlies the lithosphere |
| continental crust | thicker, but less dense than oceanic crust, made primarily of granite |
| convergent plate boundary | forms when 2 lithospheric plates come together |
| crust | outer layer of lighter rocks that covers Earth's mantle |
| divergent plate boundary | the spreading center where 2 lithospheric plates are moving apart and new lithosphere is formed |
| earthquake | the shaking of Earth's crust caused by a sudden release of energy |
| fault | a break or crack in Earth's crust along which movement has occurred |
| hot spot | area of volcanic activity near the center of lithospheric plates |
| inner core | center of the earth, made of solid iron and nickel |
| island arc | a chain of volcanic islands that forms when 2 ocean plates collide |
| lithosphere | the outer solid shell of Earth that extends to a depth of about 100 kilometers |
| mantle | the layer of rock in Earth extending from the crust downward 2,850 kilometers |
| uplifted | sedimentary rock layers are raised to higher levels with little deformation; part of mountain building |
| volcanic eruption | an opening in Earth's crust through which magma comes up to the surface |
| young mountain | mountains that are presently rising because they are at the location of converging plates pr at the site of hot spots |
| mid-ocean ridge | caused by diverging boundaries, an area of deep valleys that are broken into segments by faults |
| MOHO | the boundary between the Earth's crust and mantle |
| oceanic crust | thinner but denser than continental crust, made of basalt, subducts under continental plates |
| original horizontality | a concept that states that some rocks form in horizontal layers parallel to earth's surface, ex. lava flow |
| outer core | surrounds earth's inner core and is made of liquid iron and nickel |
| p-waves | faster, primary, compressional earthquake waves that can travel through any material |
| plate tectonic theory | theory of the formation and movement of the rigid pieces or plates that cover the earth's surface |
| plate | rigid pieces but moving, make up the earth's surface |
| lithospheric plate | rigid but broken pieces of the crust and upper mantle that move with respect to one another |
| s-waves | slower, secondary or shear earthquake waves which can travel through solids but NOT liquids or gases |
| seismic wave | waves produced by earthquakes. 3 kinds: p,s,l(surface) |
| subduction | one plate plunges beneath the other, forming a deep-sea trench |
| transform plate boundary | 2 lithospheric plates that are sliding past each other; shallow focus earthquakes are very common here |
| tsunami | a gigantic wave that results from an underwater earthquake, landslide or volcanic eruption |
| tectonic plate | the dozen or so plates that make up the surface of the earth |
