Short Answer-use a few sentences to answer each question. Be sure to use verbs and nouns in every sentence.
1. Why is a volcano fed by very viscous magma likely to be a greater threat than a volcano supplied with very fluid magma?
2. In what ways are granite and rhyolite different? In what ways are they similar?
3. Why are most magmas dominated by the same elements (silicon, oxygen, aluminum, iron)?
4. Compare a volcanic crater to a volcanic. Be clear about what each one is.
5. Describe the formation of Crater Lake. Compare it to the caldera formed during the eruption of Kilauea.
6. What is the ring of fire? Where is it?
7. How was the town of St. Pierre on the Island of Martinique destroyed by Mt. Pelee?
8. What is a fissure eruption? How does it differ from a "normal" volcano?
9. Why are crystals in pegmatites so large?
10. How are most basaltic magmas generated? That is, what process produces most mafic magmas?

Multiple Choice Question
1. Exceptionally coarse grained igneous rocks have a ________________ texture.
a. mafic
b. silicic
c. pegmatitic
d. detrital
e. aphanitic

2. Which of the following are near the bottom (low temperature end) of Bowen's Reaction Series?
a. olivine
b. amphibole
c. quartz
d. Ca-plagioclase
e. pyroxene

3. Which of the following is located above a "hot spot"?
a. Hawaii
b. Iceland
c. Mt. St. Helens
d. Mt. Etna
e. all of the above

4. What criteria are used to classify plutons?
a. grain size, mineralogy, and texture
b. chemistry, color, and weight
c. dimensions, odor, and iridescence
d. roundness, sphericity, and weathering
e. size, shape, orientation relative to existing structures

5. What is the largest of all intrusive igneous bodies?
a. dike
b. sill
c. lappolith
d. pluton
e. batholith

6. Which one of the following rocks probably underwent the fastest cooling rate?
a. granite
b. gabbro
c. basalt
d. obsidian
e. all of the above

7. Bowen's reaction series shows:
a. which minerals crystallize first as a magma cools from a liquid to a solid
b. which rocks will develop an aphanitic texture and which will form a phaneritic texture
c. why quartz, potassium feldspars, and muscovite form as mafic minerals, while olivine and pyroxene form as felsic minerals
d. which magmas will form extrusive igneous rocks and which will form intrusive igneous rocks
e. which minerals crystallize first as a magma changes from a solid to a liquid

8. The force that causes pyroclastic volcanoes to explode violently is
a. pressure from volcanic gases
b. hot convection currents in the asthenosphere that pushes magma upward
c. density differences within the magma that force part of the magma upward
d. George W. Bush
e. gravity

9. The Hawaiian Islands and Yellowstone are associated with
a. batholiths
b. subduction zones
c. hot spots
d. spreading centers
e. mid ocean ridges

10. Volcanoes occur most frequently:
a. at tectonic plate boundaries
b. where earthquakes have opened up cracks in the crust of the Earth
c. over stationary hot spots
d. in random locations throughout the Earth's oceans and coastal areas
e. in the interior parts of continents

11. The primary difference between magma and lava is:
a. one occurs at divergent plate boundaries, the other at convergent plate boundaries
b. they are produced from different parent materials
c. magma becomes lava anytime it is in a cooling condition
d. one is below the ground, the other is above ground
e. there is no difference, they are different words for the same thing

12. The reason over 50 people died when Mt. St. Helens erupted is because
a. the eruption was a complete surprise
b. the basalt flowed over the ground at high speed
c. people didn't believe the warnings and were too close
d. the eruption took place on Monday
e. the eruption was a fissure eruption

13. A dormant volcano is one that:
a. has not erupted within the last 10 years
b. has not erupted within the last 30 years
c. has not had magma moving in its vents in the last 100 years
d. has not erupted recently in geological terms, but is likely to erupt sometime in the future
e. is not likely to erupt again

14. The term viscosity refers to:
a. how heat and pressure influence a liquid's gas content
b. a liquid's resistance to flow
c. how dense a liquid is
d. how a liquid moves upward against gravity
e. how buoyant a magma is

15. Which of the following is a likely product of a volcano with extremely hot lava flowing over land near the volcano vent?
a. a basalt flow
b. pyroclastic flows
c. Pillow structures
d. Pumice
e. obsidian

16. A volcanic dome forms when:
a. a large volcanic mountain is rounded off by erosion
b. a shield volcano takes on a relatively symmetrical
c. rising magma causes a bulge in the side of a volcano
d. rising magma cools and hardens within a volcano's crater
e. a stratavolcano erupts explosively

17. What is the main reason why we are unable to predict volcanic eruptions with more accuracy?
a. we haven't developed adequate technology
b. we don't understand the inner workings of volcanoes
c. volcanoes give no warnings when they are about to erupt
d. it is economically infeasible to adequately monitor all potentially volcanic areas on continuous basis
e. some volcanoes don't produce lava when they erupt

18. The two properties used most to identify igneous rocks are:
a. color and mineral composition
b. texture and mineral grain size
c. the grain size and the number of different minerals present
d. texture and mineral composition
e. color and grain size

19. A phaneritic texture is most likely to develop in:
a. volcanic rocks
b. extrusive rocks
c. intrusive rocks
d. volcanic glass
e. partially melted rocks

20. Which one of the following igneous rocks probably underwent the fastest cooling rate?
a. granite
b. gabbro
c. basalt
d. obsidian
e. limestone

21. Gabbro is an example of an:
a. a volcanic dike
b. extrusive mafic rock
c. extrusive felsic rock
d. intrusive mafic rock
e. intrusive felsic rock

22. The geothermal gradient describes how:
a. pressure increases with depth within the Earth
b. temperature increases with depth within the Earth
c. magma becomes more mafic with depth within the Earth
d. water content increases with depth within the Earth
e. minerals crystallized in different plate tectonic environments

23. Rising magma that has forced overlying rocks to bulge upward, resulting in a domed intrusion of igneous rock is termed a:
a. diapir
b. zenolith
c. country rock
d. dike
e. banana

24. Saucer-shaped concordant plutons that sag downward are:
a. Batholiths
b. Xenoliths
c. Laccoliths
d. Lopoliths
e. all of the above

25. What is Shiprock, New Mexico, and how did it form?
a. it is a shield volcano formed by several gradual eruptions
b. it is a volcanic neck, composed of material the crystallized in a volcanic vent
c. it is pahoehoe lava formed by a single flow
d. it is a batholith formed during the Cretaceous mountain building in the Rocky Mountains
e. it is an ash flow, formed when Lassen Peak erupted in 1911

26. Which of the following is a likely product of a subaqueous basaltic eruption?
a. Pahoehoe
b. A'a
c. Pillow structures
d. Pumice
e. granite

27. If partial melting occurs, the products are a magma and some left over solid mineral material. How does the composition of the magma compare to the composition of the original (parent) rock?
a. No difference; they are identical
b. the magma is finer grained than the parent rock
c. the magma is coarser grained than the parent rock
d. the magma is more basaltic than the parent rock
e. the magma has a higher silica content than the parent rock

28. When we played with that way cool computer program we saw that volcanoes take place in most of the same places that earthquakes occur. Why?
a. earthquakes most often occur at the edges of tectonic plates
b. volcanoes occur most often at the edges of tectonic plates
c. volcanoes cause subduction
d. all earthquakes are caused by moving magma
e. only answers a and b are correct

29. In the movie we saw, it described the evacuation of Clark Air Force Base in the Philippines. Why was it abandoned?
a. because of a tidal wave
b. because of a landslide
c. because lava flow were approaching
d. because an explosive volcano began erupting on one of the runways
e. because officials were concerned about a pyroclastic flow reaching the airbase

30. How do tuff and volcanic breccia differ from other igneous rocks such as granite and basalt?
a. tuffs and breccias can be of many different compositions
b. tuffs and breccias are very low in silica
c. tuffs and breccias are finer grained than granite and basalt
d. tuffs and breccias are deposited under water
e. all of the above