Q&A Hero

Q: Carefully study the eruption visible in this figure, paying close attention to the appearance of the rocks produced when the lava solidifies and the pyroclastic materials fall to earth. Based on your analysis, would you say that the volcano has more layers of solidified lava or more layers of pyroclastic deposits? What does your answer mean for the kind of eruption style: quiescent or explosive?

Q: The volcanic islands visible here formed as a result of a mantle plume. Researchers working on these volcanic islands have collected basalt samples for potassium-argon dating to determine when these islands formed Volcanic Island A has been dated to 7.6 million years ago. Volcanic Island C dates back to 3.4 million years ago and is 200 km away from A. Using the equation Rate = Distance/Time, calculate the rate of plate motion for this region. A) 4.2 km/million years B) 47.6 km/million years C) 102.3 km/million years D) 26.3 km/million years

Q: The volcanic islands visible here formed as a result of a mantle plume. Assuming the left side of the figure is west and the right side east, in which direction is the tectonic plate is moving? A) North B) South C) East D) West

Q: The volcanic islands visible here formed as a result of a mantle plume. Which volcanic island is the oldest and subsiding into the sea? A) Volcano A B) Volcano B C) Volcano C

Q: The volcanic islands visible here formed as a result of a mantle plume. Which volcanic island is still forming? A) Volcano A B) Volcano B C) Volcano C

Q: Based on the information visible, what kind of volcano is this? A) Shield volcano B) Composite cone C) Cinder cone

Q: Using the figure of the volcano, identify the following features: lava flow, vent, conduit, and magma chamber. Match the correct term with the correct letter. A) Magma chamber B) Lava flow C) Conduit D) Vent 1. A 2. B 3. C 4. D

Q: Based on the volcanic type and construction of the flanks, what assumptions can you make about the viscosity of the lava? A) The lava is high viscosity. B) The lava is low viscosity.

Q: Based on the volcanic type and construction of the flanks, what assumptions can you make about the type of lava? A) The lava is basaltic. B) The lava is andesitic. C) The lava is rhyolitic.

Q: What kind of volcano is this? A) Shield volcano B) Composite cone C) Cinder cone

Q: How is this chain of volcanic islands forming? A) A tectonic plate is being subducted and partially melted, producing magma that rises to create a volcanic chain. B) Two tectonic plates are pulling apart, creating magma through decompression melting. C) A tectonic plate is moving over a mantle plume, which burns through the plate to create a chain of volcanoes. D) Tectonic plates are sliding past each other, generating magma, which creates a volcano.

Q: Explain why volcanic bombs take on a streamlined shape when they are flung through the air.

Q: Why are block lavas, such as an andesite lava, likely to create short, prominent flows rather than long, fluid flows?

Q: Pahoehoe and Aa can form in the same lava as it flows away from the eruptive vent. How does each form? What role does temperature play?

Q: How do scientists use earthquakes to determine if a volcano may erupt soon?

Q: Volcanic island arcs and continental volcanic arcs are both associated with convergent plate boundaries. However, the lavas that their volcanoes erupt are different. Where does the lava come from for each type of volcanic arc?

Q: Explain how sulfur dioxide gas erupted from a volcano can affect global climate.

Q: How does decompression melting generate magma at rift zones?

Q: How does a volcanic neck form? What happens to the rest of the volcano that originally surrounded it?

Q: Provide three examples of how lahars can form.

Q: What materials make up a pyroclastic flow?

Q: Composite cones are famous for their conical shapes with steep summits, sloping flanks, and broad base. How might the composition of eruptive materials have changed for the volcano to transition from something with a broad base to something with a smaller base and steeper slopes?

Q: What material makes up the flanks of cinder cones? Why does magma rising through the conduit of a cinder cone volcano often break through the side of the volcano and flow down the flank?

Q: How do lava tubes form in basaltic lavas? How can the exterior solidify if the interior is still fluid?

Q: Assume you live near Mount St. Helens and the volcano is going through an explosive eruption. Explain the effect pyroclastic materials would have on your home.

Q: Kilauea, a volcano in Hawaii, generates fluid, extensive lava flows. Mount St. Helens, a volcano in Washington State, can produce lava flows that are short and thick, but that can also erupt violently and generate large volumes of ash. What might these differences indicate about each lava's silica content and temperature?

Q: How will the water vapor in magma reduce the viscosity of the magma?

Q: Differentiate the three types of magma based on igneous composition and silica content.

Q: Explain what will happen to the flanks of the volcano as magma moves into the magma chamber.

Q: Based on the eruptive materials, volcanic hazards, and violence of eruptions, which type of volcano would be the most dangerous to live near? Cite specific hazards and how they could affect nearby residents.

Q: Compare and contrast the three types of volcanoes (shield, cinder cones, and composite cones). Make sure to comment on the differences in size, shape, and slope angle.

Q: What is the importance of monitoring volcanic activity? Why should we pay attention to what volcanoes are doing?

Q: What is the difference between a pyroclastic flow and a pyroclastic surge (aka surges)?

Q: What is the difference between a quiescent and an explosive eruption?

Q: Match the volcano name with the volcano type for the following questions. Choices will be used more than once. 1. Mount Hood 2. Mauna Kea 3. Parcutin 4. Cerro Negro 5. Newberry Volcano 6. Mount Etna A) Cinder cone B) Composite cone C) Shield volcano

Q: Match the volcanic hazard with its definition. 1. Pyroclastic flow 2. Lahar 3. Tsunami 4. Ash Falls 5. Volcanic Gases A) Substances like CO2, SO2, Cl, and F that can result in climate change and be hazardous to human health B) Large volumes of ash precipitating from eruption cloud C) Fluid mudflow of volcanic debris D) Hot, fast-moving body of expanding gas and ash that hugs the flanks of the volcano E) Destructive sea wave triggered by powerful explosions or landslides into large bodies of water

Q: Match the following pyroclastic materials in order from smallest to largest. 1. Volcanic bombs 2. Ash 3. Lapilli A) Neither smallest nor largest B) Smallest C) Largest

Q: Composite cones are also known as stratovolcanoes.

Q: Most cinder cones have eruptive phases that last for centuries.

Q: The more the silica in magma, the lower the viscosity.

Q: Along which tectonic boundary would the greatest amount of magma be generated every year? Why? A) Transform boundaries: magma produced from friction B) Convergent boundaries: magma produced by dehydration of plate water and partial melting C) Divergent boundaries: magma produced by decompression melting

Q: How is a volcanic neck different from a volcanic pipe? A) Volcanic necks are longer and bring materials up from the mantle. B) Volcanic pipes connect to shallow magma chambers. C) Volcanic pipes are shorter. D) Volcanic necks are shorter and connect to shallow magma chambers.

Q: You are in charge of emergency planning in Electron, Washington, when it is brought to your attention that the entire town is built upon the remains of eruption materials from Mount Rainier, which is less than 30 miles away. Using the past volcanic hazard history of Mount Rainier, which volcanic hazard would most likely affect your town? A) Pyroclastic flow B) Lahar C) Lava flow D) Volcanic landslide E) Earthquakes

Q: When Eyjafjallajkull erupted in March 2010, ash plumes drifted southeast over Europe and, as a result, the controlled airspaces over many European countries were closed to air traffic, stranding thousands of people worldwide. Why would flying a commercial jet through a cloud of volcanic ash be dangerous? A) Ash can impede visibility if thick enough. B) Hot ash will cause the plane to catch fire. C) Abrasion of windows and engine parts from ash. D) Engines can be clogged by ash. E) Ash impairs visibility, clogs engines, and abrades engine parts.

Q: What substances are emitted from fumaroles? A) Lava B) Ash C) Water D) Volcanic gases

Q: Kilauea is a volcano created by ________. A) intraplate volcanism B) subduction C) rifting D) shear forces

Q: Which of the following statements about lava domes is true? A) Lava domes can only collapse during eruptions. B) Lava domes can collapse during eruptions or in quiet periods between eruptions. C) Lava domes are most commonly associated with cinder cone volcanoes. D) Lava domes are created by earthquakes.

Q: Secondary vents on composite cones can generate ________ volcanoes. A) shield B) cinder cone C) additional composite cone

Q: Which of the following eruptive materials can be associated with cinder cone volcanoes? A) Ash B) Lava flows C) Scoria fragments D) Lava flows and scoria fragments E) Ash, lava flows, and scoria fragments

Q: Which volcanic type(s) can have pyroclastic ejections during eruptions? A) Shield volcanoes B) Cinder cones C) Composite cones D) Cinder and composite cones E) Shield volcanoes, cinder cones, and composite cones

Q: ________ are small vents that emit volcanic gases. A) Calderas B) Domes C) Fumaroles D) Tuff

Q: Which of the following eruptive materials can be described as basaltic, vesicular ejecta found around cinder cone volcanoes? A) Tuff B) Scoria C) Lapilli D) Pumice

Q: Pyroclastic materials are generally associated with which type of magma(s)? A) Basaltic B) Andesitic C) Rhyolitic D) Andesitic and rhyolitic E) Basaltic and andesitic

Q: GPS units, satellites, and lasers are some of the tools used to monitor the ________ of the volcanic flanks, which indicates magma accumulating in the magma chamber. A) gas content B) temperature C) inflation D) mineral content

Q: Which of the following changes are not evidence of migrating magma? A) Changes in the pattern of earthquakes produced by moving magma B) Molten rock flowing down the flank of a volcanic cone C) Increase in ground temperature D) Changes in the volcanic gases released from the volcano

Q: How is magma generated along subduction zones? A) Decompression melting of the mantle from weight reduction. B) Fluids are dehydrated out of the descending plate, which lowers the melting point of the surrounding mantle. C) Friction from colliding plates melts mantle material. D) Radioactive decay melts mantle material.

Q: What type of lava is produced at a divergent plate boundary? A) Rhyolitic B) Andesitic C) Basaltic

Q: Along which tectonic boundary will chains of composite cone volcanoes be located? A) Convergent boundary B) Divergent boundary C) Transform boundary D) Mantle plumes

Q: What kind of volcanic hazard can be triggered by the collapse of a lava dome? A) Pyroclastic flow B) Lava flow C) Ash fall D) Earthquake

Q: What would happen to the peridotite if there was a decrease in pressure from that at the depth of 100 km?

Q: At what temperature will peridotite melt along the geothermal gradient?

Q: Follow the geothermal gradient to the depth of 100 km. In which state of matter will peridotite exist at 100 km?

Q: Explain the processes occurring in the figure above that are generating magma. At what kind of tectonic boundary are such processes common?

Q: Identify the igneous textures visible in Images A, B, and C in the figure above. 1. A 2. B 3. C A) Glassy B) Vesicular C) Aphanitic

Q: Using the figure above, fill in the missing substances from Bowen's reaction series. A) Olivine B) Biotite mica C) Quartz D) Calcium-rich plagioclase 1. A 2. B 3. C 4. D

Q: What is the igneous composition of the rock in the above image?

Q: Is the rock in the above image intrusive or extrusive?

Q: Why would rhyolite deposits be less common than granite deposits?

Q: All rocks are classified according to ________ and ________.

Q: Of the following substances, which are the common elements in igneous rocks? Silicon, rubidium, nitrogen, carbon, sodium, manganese, hydrogen, oxygen, potassium, calcium, phosphorous, aluminum, iron, chlorine, magnesium, uranium, helium, gold

Q: List the intrusive igneous textures below. Phaneritic, aphanitic, glassy, pyroclastic, pegmatitic

Q: Slow cooling produces ________ crystals, whereas fast cooling produces ________ crystals.

Q: How does the presence of silica affect the temperature and viscosity of magma?

Q: Magma can form up to 250 km deep in the Earth. If magma forms at such a depth, how can magma at that depth rise through the mantle and the crust toward the surface?

Q: How does magma differ from lava?

Q: In July 1863, Union and Confederate forces fought in a three-day battle at Gettysburg, Pennsylvania. The Confederate position was on Seminary Ridge, an igneous dike. The Union position was on Cemetery Ridge, an igneous sill. Using what you know about the history of the battle, interpret how the geology of the battlefield aided the Union victory.

Q: Magma that forms batholiths forms in the mantle and must migrate upward. However, the sedimentary and metamorphic rocks that surround these batholiths are only moderately deformed. How does a rising magma body make its way through several kilometers of solid rock to be emplaced as a batholith? (Start your journey in the mantle.)

Q: What are two ways a primary magma can be generated?

Q: How will mantle-derived magma change when it ponds against crustal rocks?

Q: How could a researcher use magmatic differentiation to determine if a batholith is the result of one body of magma cooling and crystallizing or multiple bodies of magma?