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41 Cards in this Set
- Front
- Back
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What are Volcanoes? |
Extrusive Igneous Rocks |
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What determines what type of volcano will form? |
Type of Magma (Silica content) |
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What type of Silica content produces a violent volcano? |
High Silica (70%-60% - Felsic to Andesitic) |
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What is viscosity? |
The "flow" ability of a liquid (refers to the thickness) |
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Give an example of a liquid considered to have High Viscosity and determine it's flow rate |
Syrup, flows slow |
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Give an example of a liquid considered to have Low Viscosity and determine it's flow rate |
Water, flows fast (easier) |
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What type of magma is associated with Violent Eruptions (type of viscosity)? |
High Viscosity |
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What type of magma is associated with Non-Violent Eruptions (type of viscosity)? |
Low Viscosity |
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What type of Silica content produces a non-violent volcano? |
Low Silica (50% - Mafic/Basaltic) |
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What can be said about the relationship between Silica Content and Viscosity? |
High Silica Content = High Viscosity = Violent Erupting Volcanoes Low Silica Content = Low Viscosity = Non-Violent Erupting Volcanoes |
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Name the Three types of volcanoes |
Shield, Composite Cone and Cinder Cone |
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List the types of eruptions for each of the three volcano types |
Shield - Non-Violent Composite Cone - Violent Cinder Cone - Non-Violent |
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What are pyroclastics? |
Magma that explodes into the air and cools - Fire Formed Rocks |
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Pyroclastic Classifications |
-Ash - Smallest -Cinders (gravel/sand size) - larger than ash -Blocks (into air as solid) - 2.5 inches or larger (tennis ball or larger) - larger than Cinders -Bombs - (into air as liquid - form solid after being in the air) - 2.5 inches or larger - larger than Blocks |
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Shield Volcano - Type of Silica Content and size compared to three types? |
Low Silica Content (50% - Mafic/Basaltic) Size: Largest |
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Shield Volcano - Type of Magma? |
Mafic or Basaltic (Low Silica Content) |
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Shield Volcano - Magma Viscosity? |
Low Viscosity |
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Shield Volcano - How Many Pyroclastics? |
Not many |
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Shield Volcano - Name an example of this type of Volcano |
Hawaii |
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Composite Cone - Type of Silica Content and size compared to three types? |
High Silica Content (70%-60% - Felsic to Andesitic) Size: Mid-sized |
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Composite Cone - Type of Magma |
Felsic to Andesitic (High Silica Content) |
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Composite Cone - Magma Viscosity? |
High Viscosity |
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Composite Cone - How many pyroclastics? |
Lots/Many |
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Composite Cone - Has Layers of... |
Pyroclastics and Lava |
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Composite Cone - Name an example of this type of Volcano |
Mt. St. Helens (WA), Mt. Rainier (WA), Mt. Fuji |
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Cinder Cone - Size compared to three types? |
Smallest |
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Cinder Cone - how are they formed? |
Formed from cinders or pyroclastics |
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Cinder Cone - where does lava flow from? |
The base of the cone |
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Cinder Cone - what is true about the their formation? |
They often occur in groups (NM and AZ have lots of them) |
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Cinder Cone - name a unique place they can form |
Can occur on tops of Shield Volcanoes |
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What is a Caldera? |
A large collapsed depression having more or less a circular form - same as a crater but with a diameter of more than a 1/2 mile |
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What is a Crater? |
A steep walled depression at the summit of a volcano |
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What is a Vent? |
The surface opening of a volcano |
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Name the types of Lava Flows and their Flow Rate |
-aa (looks blocky - think ah, ah, like it hurts) -slow moving -pahoehoe (looks smooth and ropy) -faster moving than aa |
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What is a Lahar? |
Mud flow composed of water from the melting snow and ash (cannot be outrun) |
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What is Pyroclastic Flow? |
Ash & Hot Gas (cannot be outrun - speeds up to 100 mph and faster) |
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What is a Fissure Eruption? |
Eruptions in the Earth coming from fissures (or cracks/fractures) in the Earth's surface/crust (by far the greatest volume of volcanic material is extruded from fissure eruptions) |
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What type of fracture does a Fissure Eruption erupt from? |
Linear Fracture |
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What is a Flood Basalt? |
Massive accumulations of basaltic lava (from Fissure Eruptions) |
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What is a volcanic Pipe? |
Conduits (often short) that connect a magma chamber to the surface |
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What is a Volcanic Neck? |
The exterior of a volcanic Pipe after years of erosion. Due to the type of rock formed along a pipe (due to contact), this is much more resilient than the outer layers of a structure which is why this "Neck" is left standing. Ex: Ship Rock, NM |
