Download Volcano Review sheet - new for 2016-17

Volcano Review – you need to update your “I Can” after completing this sheet!
Fill-in-the-Blank
1. Mount Shasta and Mt. St. Helen are examples of __________ volcanoes
2. It would take the addition of a lot of water to turn a pyroclastic flow into a ________________.
3. The three main controlling factors on explosivity of volcanoes are ______________________,
________________________ and the ________________________________ in the magma.
4. The majority of our destructive volcanoes in HUMAN history have been _____________________.
5. Wizard Island is a ________________ ______________ volcano that formed in the collapsed
________________ at Crater Lake, and that type of volcano rarely exceeds ______________feet in height.
6. Volcanic ash is dense, and can collapse houses. Name 3 other problems it causes, and the spheres it
impacts.
7. Signs of a volcano include gases being emitted from a volcano through vents called
______________________, ________________________ due to magma moving through the ground,
______________________ where steam is coming out of the ground and pushing liquid water ahead of it.
8. More __________________ makes lava more viscous, which is a characteristic of which magma?_____.
9. All of the recent volcanoes in the US are west of the Mississippi River and ___________________ is the
state with the majority of those volcanoes.
10. (11). Sulfur dioxide getting into the atmosphere from volcanic explosions can cause acid rain. How can
acid rain damage each of the 4 spheres of the earth?
11 (12). This is the sharp sort of lava ________________________, and the dull lava is called
______________
12 (13). I find a rock that has a lot of silica (75%) in it and is sitting on a big volcano. In which type of volcano
would it be most likely to be found? ____________________, and on what type of crust?_____
13 (13.5) The _________ of a volcano is a special type of crater caused by the collapse of lava in the conduit.
Multiple Choice
14. If I cut some granite from a granite mountain, and the granite has a lot of very large crystals in it, which of
the following items MOST LIKELY applies to my situation?
A. This is an extrusive igneous rock that cooled quickly
B. This is an extrusive igneous rock that cooled slowly
C. This is an intrusive igneous rock that cooled quickly
D. This in an intrusive igneous rock that cooled slowly
E. This is a metamorphic rock that cooled quickly
AB. This is a metamorphic rock that cooled slowly
AC. This is a sedimentary rock, since they are the only rocks that have very large crystals in them
15. Rhyolite is an extrusive felsic (light color) rock that’s more like granite than like obsidian. Do you expect to
find more or less silica in rhyolite than you would find in a mafic (dark) rock like obsidian or basalt?
A. More
B. Less
C. It will vary by rock sample
D. None of these
16. Why are shield volcanoes usually formed on oceanic crust?
a. They don’t stick to continental crust, so they slide off into the ocean
b. Continental crust is too hard
c. Continental crust has too much silica, which makes for destructive explosions and also gives it lack of
ability to have lava flow properly to make such a volcano
d. None of the above
17. What is a supervolcano?
A. A volcano that can have eruptions which are many times greater than any volcano in recent times.
B. A very old volcano that has magical powers.
C. A big shield volcano that is similar to those we see in Hawaii.
D. A volcano on a supercontinent.
18. SiO2 is known as silica, which makes up about __________________ of basalt and is a greater percentage
of granite. Adding more SiO2 will make magma more ____________________. Also, since silica is
_________________ dense than some of the minerals commonly found in basalt, replacing some of
basalt’s other minerals with silica will make the new rock ____________ dense than basalt. Given those
facts and your knowledge of granite, basalt, density, and viscosity, it should be a logical conclusion that:
a. Granite-based magma will be a major portion of shield volcanoes, like in Hawaii, and its additional
percentage of silica will make it erupt more gently.
b. Basalt will float on granite and volcanoes made with a lot of basalt will erupt gently
c. Basalt is the best choice to make a stratovolcano, since it has the best viscosity and density for making a
stratovolcano.
d. Lower density rock will have less silica, since the relationship of silica to density is a direct relationship
(when silica content goes up, density goes up).
e. Granite will float on basalt and volcanoes made with a lot of granite will tend to be more viscous, and
therefore more likely to become composite volcanoes