Geography homework

4. A great wave that washes away anything in it's way
6. A volcano that has erupted recently and is likely to erupt again
8. A vent in the suface of the earth
9. Mudflow formed of a mixture of water and volcanic ash
11. A verticle conduct through the earth's crust below a volcano
14. A volcano that has erupted within historic times (in the last 2,000 years) but not recentlyextinctvolcano a volcano that has not erupted in historic times and is not expected to erupt again
17. The outer layer of the earth
18. A process where heat is created when objects rub together
20. The cntral part of the earth

1. Magma which has reached the earth's surface through a volcanic eruption
2. A passage followed by magma in a volcano
3. A volcano that has not erupted in historic times and is not expected to erupt again
5. The theory that horizontal movement of the earth's surface causes slow, relative movements of the continents toward or away from one another
7. A crack or fracture in the earth's surface. Movement along the fault can cause earthquakes or--in the process of mountain-building--can release underlying magma and permit it to rise to the surface
10. An instrument that records seismic waves; that is, vibrations of the earth.
12. Shaking of the Earth's surface as a result of the sudden release of stresses built up in the Earth's crust
13. A surface of fracture in a rock
15. The zone of the earth below the crust and above the core
16. Fine material thrown out by a volcano
19. Low amplitude, continuous earthquake activity often associated with magma movement.