Volcanoes and Volcanism - The Changing Earth: Exploring Geology and Evolution - page 130

5. An incandescent cloud of gas and particles erupted
from a volcano is a
a. _____ spatter cone;
b. _____ lapilli;
c. _____ nuée ardente;
d. _____ caldera;
e. _____ volcanic tremor.
6. Pillow lava forms when
a. _____ thick layers of pyroclastic layers
accumulate;
b. _____ lava erupts under water;
c. _____ globs of lava stick together on a lava fl ow's
surface;
d. _____ pressure within a fl ow causes its surface to
buckle;
e. _____ a volcano's summit collapses.
7. Which one of the following is one of Earth's main
volcanic belts?
a. _____ Appalachian belt;
b. _____ East African belt;
c. _____ Indian Ridge belt;
d. _____ East Pacifi c belt;
e. _____ Mediterranean belt.
8. A small, steep-sided volcano made up of pyroclastic
materials is a
a. _____ cinder cone;
b. _____ lava dome;
c. _____ shield volcano;
d. _____ caldera;
e. _____ nuée ardente.
9. Volcanoes emit several gases, but the most common
one is
a. _____ carbon dioxide;
b. _____ fl uorine;
c. _____ hydrogen sulfi de;

d. _____ water vapor;
e. _____ methane.
10. The Hawaiian volcanoes are made up mostly of lava
that cools to form
a. _____ rhyolite;
b. _____ granite;
c. _____ basalt;
d. _____ welded tuff;
e. _____ andesite.
11. Why are eruptions of mafi c magma rather quiet, whereas
eruptions of felsic magma are commonly explosive?
12. How do columnar joints and spatter cones form?
Where are good places to see each?
13. Why do shield volcanoes have such gentle slopes,
whereas cinder cones have very steep slopes?
14. What does volcanic tremor indicate, and how does it
differ from the shaking caused by most earthquakes?
15. Suppose that you fi nd rocks on land that consist of
layers of pillow lava overlain by deep-sea sedimentary
rocks. Where and how did the pillow lava form, and
what type of rock would you expect to fi nd beneath the
pillow lava?
16. What criteria are used to assign a volcanic explosivity
index (VEI) value to an eruption? Why do you think
that the number of fatalities and property damage are
not considered when assigning a value?
17. Explain what types of volcanoes form at divergent and
convergent plate boundaries. What accounts for the
difference(s)?
18. What kinds of information do geologists evaluate when
they monitor volcanoes and warn of imminent erup-
tions?
19. How does a caldera form? Where would you go
to see one?
20. What is a lava dome and why are they so dangerous?