Introduction to Volcanology
Definition of a volcano
Requirements for volcanism
Descriptions of volcanoes - active, extinct, dormant, live, erupting
Earliest written vs. earliest known record of volcanism
Why is volcanism important?

Eruption types:
Icelandic, Hawaiian, Vulcanian, Strombolian, Pelean, Plinian

Volcanic landforms:
Shield volcanoes, cinder cones, composite volcanoes (stratovolcanoes), domes

Plate tectonic setting of volcanism
Structure of the Earth
Subduction zones, spreading centers (continental and oceanic), hotspots (continental and oceanic)
Characteristic eruptions from different plate tectonic settings

Physical properties of magmas

• Definition of a magma - parts that make up magma (liquid, solid, gas)
• What is a silicate liquid? Be able to describe linked silicate tetrahedra and why they are important
• What are phenocrysts, and what can they tell us about a magma's history?
• Why is obsidian (rhyolitic glass) more common than tachylite (basalt glass)?
• What are the volatile (gaseous) components of magmas? What are the most abundant gases? How do these gases occur (dissolved in the magma or exsolved as bubbles/vesicles). How much can be dissolved? How are exsolved gases measured? When are gases more soluble (hi pressure/low pressure?, hi temperature/low temperature?) and why is this important for eruptions.
• Know what vesiculation means.
• Magma composition - rhyolite, dacite, andesite, basalt.
• Have an idea of temperatures of these different compositions. Know the difference between a liquidus and a solidus.
• Don't memorize viscosity numbers, but do understand how viscosity changes with composition and why.
• What is the difference between a Bingham and a Newtonian fluid? What is yield strength?
• What does H2O do to the viscosity of a magma? CO2? Why?
• How do phenocrysts affect viscosity? How does temperature affect viscosity?
• What is the difference between laminar and turbulent flow?

Basalt as the parent to other magma types

• Komatiites and Carbonatites - what are they and what is interesting about them?
• Terrestrial basalts - what are MORB, OIB, IAB, CRB?
• What is the current hypothesis for the formation of the lunar mare (basalt plains)?
• Where do basaltic meteorites come from?

• Effusive vs. explosive, conventional vs. hydrovolcanic, central vent vs. fissure, polygenetic vs. monogenetic
• Know the difference between magnitude, dispersive power, and intensity
• Know definitions of the following terms:

Pumice, scoria, spatter, ash, lapilli, bomb/block, tuff, lapillistone, lapilli tuff, breccia, bread-crust bomb, cow-dung bomb
• Hydrovolcanic eruptions
• Phreatic eruption
• Surtseyan eruption - know style of eruption and how they evolve with time
• Phreatoplinian eruption
• Subglacial eruptions (including jokulhlaups)

• Be able to explain a Hawaiian eruption and a Strombolian eruption, and the difference between them. Include magma type, magma viscosity, size of volcanic edifice, duration of flows, duration of eruptive event, etc.
• How do pyroclastic deposits of Hawaiian eruptions depend on eruption rate (i.e., low eruption rates vs. moderate vs. high)
• What is the present style of eruption on the Big Island of Hawaii?
• How do flood basalt eruptions differ from Hawaiian and Strombolian eruptions?
• Describe in detail the differences between aa and pahoehoe lavas. (include discussions of temperature, viscosity, and gas content).  Know what pseudoplastic means
• Basalt lava features - lava tubes, tumuli, lava tree molds, lava terraces
• Jointing - parallel (result of solidification), columnar (result of post-solidification cooling)

Andesite lavas

• Differences from basalt - relative velocities, yield strengths, presence or absence of pahoehoe, aa, blocky lavas, lava tubes

Dacite lavas

• Differences from basalt/andesite - relative velocities, yield strengths, presence of domes
• Association with explosive eruptions

• Endogenous vs. exogenous
• Low domes, coulees, Peleean domes, upheaved plugs (plug domes)
• Cryptodomes
• Results of dome collapse

• Scarcity because of explosiveness of rhyolitic magmas
• Devitrification and hydration, what are they and how would you recognize them?
• Perlite, apache's tears.  What are they?

• What are the important variables in pyroclastic eruptions?
• Describe Plinian, Strombolian, Vulcanian eruption columns and the mechanisms that produce them

• Dynamics - gas thrust region, convective region, umbrella region
• How does width of eruption column vary upwards?  What does height of eruption column depend on?
• Definition of tephra, isopleth, isopach, terminal velocity, clast-support envelope.
• How does size of eruption column control distribution of tephra fallout from a Plinian column?



UP TO HERE FOR EXAM 1 in 2004

• How does wind control distribution of tephra fallout from a Plinian column? Is tropospheric wind or stratospheric wind more important in deflecting Plinian columns?
• Why is the understanding of eruption columns and their fallout so important to aircraft safety? Why is the ash dangerous to aircraft?
• If you were a brand new volcanologist sent to map tephra deposits from a Plinian eruption, what would you do?  Why? (i.e., what would be your mode of attack for this project? What four features would you look for/measure?  Why?)
• Be able to locate where deposits from a particular type of pyroclastic eruption should fall on a Pyle diagram (i.e., understand the diagram)
• How do the pyroclastic deposits (not lava flows) from a Hawaiian, Strombolian, Vulcanian, Plinian, Surtseyan, and Phreatoplinian eruption differ? (i.e., characterize each).