UNIT TEST NAME: _________________________

THE GREAT VOLCANO EXAM - "IT'S HOT!"

____ 1. As the silica content increases, molten rocks tend to become:

a. thinner and lighter in color c. thicker and lighter in color

b. thinner and darker in color d. thicker and darker in color

____ 2. Where is molten rock LEAST likely to form?

a. within the asthenopshere c. on the surface

b. at plate boundaries d. under hot spots

____ 3. Large thunks of molten rock are thrown into the air from the eruption of the volcano. This liquid rock is called:

a. blocks b. ash c. bombs d. lapilli

____ 4. Debris that is erupted from the volcano and is found in a large variety of sizes is known as:

a. gas b. tephra c. magma d. lava

____ 5. One of the gases NOT found in volcanic activity is:

a. oxygen b. potassium c. hydrogen d. sulfur dioxide

____ 6. Molten rock under the ground is called:

a. lava b. iron c. basalt d. magma

____ 7. Molten rock that is ejected from the volcano is called:

a. lava b. iron c. basalt d. magma

____ 8. In the movie "Volcano Watchers", the lake they floated their raft on was comprised of a large amount of what form of gas?

a. hydrogen gas c. carbon monoxide gas

b. sulfuric gas d. carbon dioxide gas

____ 9. Lava that forms into smooth, rope-like rock layers.

a. Aa b. dike c. sill d. pahoehoe

____ 10. When magma flows into horizontal cracks in the rock formation.

a. lava b. dike c. sill d. laccolith

____ 11. Magma that is high in silica content is known as:

a. mafic b. mega-silicate c. lapillic d. felsic

____ 12. Magma that is low in silica content is known as:

a. felsic b. mafic c. viscous d. silica-free

____ 13. Magmas containing large amounts of gases tend to produce explosions that are:

a. less explosive c. more explosive

b. none explosive d. gases make no difference

____ 14. Lava is slightly different from magma because:

a. some gases have escaped in the transformation

b. the lava has changed to a bright blue color

c. lavas are always water-like rather than thick magma

d. lava is cool; magma is red-hot

____ 15. Gases tend to:

a. move easily in thick magma c. move easily in thin magma

b. not be found in any magma d. be unimportant to an eruption

____ 16. Thin magma that erupts through long, narrow fractures is a characteristic of what type of volcanic eruption?

a. Subduction Boundary b. Hot Spots c. Rift d. Composite

____ 17. Thick magma that erupts through the overlap of two plates is a characteristic of what type of volcanic eruption?

a. Subduction Boundary b. Hot Spots c. Rift d. Composite

____ 18. Thin magma that erupts through the mid-portion of a continental plate is a characteristic of what type of volcanic eruption?

a. Subduction Boundary b. Hot Spots c. Rift d. Composite

____ 19. Rift eruptions are most commonly associated with what type of volcanic mountain (formation)?

a. Composite b. Rift c. Cinder Cone d. Shield

____ 20. Subduction boundaries are most commonly associated with what type of volcanic mountain (formation)? a. Composite b. Rift c. Cinder Cone d. Shield

____ 21. Hot Spots are most commonly associated with what type of volcanic mountain (formation)?

a. Composite b. Rift c. Cinder Cone d. Shield

____ 22. The rock masses that form when magma cools inside other rocks.

a. plutons b. ash c. lapilli d. blocks

Match the following magma formations to their meaning

____ 23. Sills a. bulge the surrounding rock layers

____ 24. Dikes b. cut vertically across rock layers

____ 25. Laccolith c. form the cores of major mountain ranges

____ 26. Batholith d. parallel to the layers they intrude