| A | B |
|---|
| core | center of the earth, formed of hot iron mixed with other metals |
| mantle | rock layer about 1,800 miles thick between the earth's core and the crust |
| crust | uppermost layer of the earth |
| magma | hot, melted rock that sometimes flows to the earth's surface in a volcanic eruption |
| continent | massive land area |
| plate tectonics | theory that the earth's crust is not an unbroken shell but consists of plates, or huge slabs of rock, that move |
| earthquake | violent and sudden movement of the earth's crust |
| tsunami | huge sea wave caused by an earthquake on the ocean floor |
| fault | crack in the earth's crust |
| weathering | natural process that breaks surface rocks into boulders, gravel, sand, and soil |
| erosion | process of wearing away or moving weathered material on the earth's surface |
| glacier | giant slow moving sheet of ice |
