Exam III review questions

10-point questions

1. What effect does plume height have on the dispersal of lithic clasts? How does this differ form the effect on pumice?

2. What causes a pyroclastic flow to become welded?

3. Why are some surge deposits classified as "wet" type and others as "dry"? What are the fundamental factors that help to define in this distinction?

4. Define the following terms (other definitions are possible):

a. Log normal size distribution

b. Isopleth

c. Isopach

d. Ballistic trajectory

e. Terminal fall velocity

f. Potential energy of a volcanic cloud

5. Compare and contrast the volcanic products on Io and Europa. Why are both of these small planets still volcanologically active?

6. Other short factual 10-point questions may be used.

15-point questions

1. Draw a diagram of a large eruptive plume and label the main parts. Indicate which processes occur in each part of the plume and the effect on its rise.

2. How can you easily distinguish fall, flow, and surge deposits in the field? Use criteria from distribution, clast texture, bedding, and grain-size in your answer.

3. The 1980 eruption of Mount. St. Helens has become the classic example for the formation of a volcanic debris avalanche. Describe the cause of this event at MSH giving a time line for each critical event.

4. Discuss rheology in the context of lahars. Explain the technical meaning of viscosity and yield strength. What factors control the path, length, and velocity of lahars, i.e. relate your explanation to the difference between cohesive and non-cohesive lahars. Explain how the texture and morphology of a lahar deposit can give some insight into its properties when it was moving.

5. Name four of main classes of economic mineral deposits associated with igneous/volcanic activity. For each give: a). Their main economic chemical elements, b). Environment of formation (depth, size, etc.), and c). Type of associated igneous body.

6. Pick one Cascade volcano, other than Mount St. Helens, and describe the following: a) morphology, b) eruption history (size and frequency of events), c) eruption types, and d) associated hazards

7. What is a lunar "sinuous rille"? Briefly discuss 3 models for its genesis.

20-point questions

1. Volcanic debris avalanches and mudflows have many similarities and differences. These two phenomena may even grade one into the other. Make a table comparing several aspect of each type of phenomena and its deposits. Given an example of a debris flow without an avalanche, an avalanche without a debris flow, and a debris flow associated with an avalanche. What factors caused the differences in these three events?

2. Answer the following questions involving an energy line calculation.

A. Given the elevation data in the table below, plot the topographic profile.

B. Assuming that an avalanche will start at the summit, plot the energy line for the case of a Heim coefficient of 0.20.

C. Show the zones of acceleration and deceleration of the avalanche on the profiles.

D. What is the maximum velocity reached by each avalanche?

E. What is the final distance reached by the avalanche?

Elevation (m)	Distance (m)
5000	0
3000	2000
2500	4000
2200	6000
1800	10000
1500	20000

3. Give a classification of eruption plume types describing the following main features: Column height, size of fragments, dispersal of products, and style of explosions.

5. Define the following terms (other definitions are possible):

a. Log normal size distribution

b. Isopleth

c. Isopach

d. Ballistic trajectory

e. Terminal fall velocity

f. Potential energy of a volcanic cloud

6. Explain the four main stages of scoria cone growth according to McGetchin

7. What are the important characteristics that distinguish volcanic debris flow deposits and volcanic mudflows from ignimbrites? Which properties demarcate volcanic debris flow deposits and volcanic mud flows from each other? How can the risk associated with volcanic debris flow deposits and volcanic mudflows be reduced?

8. Volcanism on the Earth, the Moon, Venus, and Io are extremely different in terms of planetary history, form, type, composition, and frequency. Describe the major types of volcanoes on these 4 planets. Give an explanation for the difference between them.

9. How are deposits of cohesive debris flows, non-cohesive debris flows, and hyperconcentrated stream flows distinguished? What are the characteristics of each type of flow? How are the deposits of each flow type distributed in relation to the volcanic source region?

10.Compare and contrast the volcanic styles of the Earth, the Moon and Mars. Consider the volcanic products, eruption styles, and tectonic settings.