Study Questions for Exam II
20-point questions 1. Discuss the differences between maars, tuff rings, and tuff cones. In your discussion, explain how all of these might be found at a single volcano.
2. Discuss the different volcanic styles at fast-, intermediate- and slow-spreading centers (be sure to define these terms!). Include eruptive volume, frequency, and emplacement style, and how this relates to the general volcano-tectonic morphology of the ridge axis.
3. Name 4 different volcanic eruption types. For each type: a) give an example of a specific (date and place) eruption that fits the classification, b) indicate the relative abundance of lava and pyroclasts involved. c) Describe the eruptive column, and d) describe the products.
4. Describe the relationship between the water and melt mixture that leads to a fuel/coolant interaction (FCI). Quantitatively explain the role of conversion of thermal energy to kinetic energy in your answer. Your answer should also discuss the causes and results of melt (or rock) fragmentation.
5. Rheology. For each of the following rheologic models do the following. A) Draw a rheogram, make a block diagram of a simple model, give an equation relating stress to strain or strain rate, and list a natural example of a material with that behavior.
Newtonian material
Elastic Material
St. Venant material15-point questions 1. Compare and contrast the formation and evolution of calderas on the top of basaltic shield volcanoes to those of resurgent caldera.
2. What is the stratigraphy of a typical tuya or table mountain? Why do the different layers occur at the depths at which they are found?
3. What happens during a fissure eruption? Include what happens to the rising dike, what observations are made on the ground, and how the eruption progresses.
4. How does knowledge of the composition (chemistry, volatiles, and crystals), repose time, volume, and rheology (viscosity) of magma help us to understand the factors that controlled the AD 79 eruption of Vesuvius? Explain change from an initial catastrophic phase with highly to moderately fractionated pumice in a plinian column that was followed by a column collapse phase with pyroclastic flows and surges. What conditions at AD 79 were different from those between 1631 and 1944 when Vesuvius produced only relatively quiet small basaltic scoria cones and lava flows?
5. Compare and contrast the 1980 eruption of Mount St. Helens with the 1903 eruption of Mt. Pelée. Consider the precursors, the size of the eruptions, the eruption styles (types of products), and the effects on the surrounding population.
10-point questions
1. Describe the different types of lava domes? What controls whether domes grow exogenously or endogenously? What is primarily responsible for the different morphologies of lava domes?
2. Explain the effect of magma temperature, pressure, and composition, can effect explosive eruptions using some detail. Be careful to be as complete as possible. Give an example of an actual eruption that illustrates the role of each factor.
3. What is meant by Bingham behavior? Draw a rheogram for a Bingham material.
4. Identify a few minerals from their EDAX spectra.