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48 Cards in this Set

  • Front
  • Back
90% of volcanism is associated with...
the edges of techtonic plates
The other 10% of volcanism is situated...
over hot spots
80% of the earth's magma comes out of
spreading center
Water lowers the melting point of
Economic loss is mostly caused by
peaceful eruptions
Why aren't volcanoes right next to the edge of a trench?
Because the magma has to be able to get hot enough to create a volcano.
Are basaltic rocks explosive? Why or why not?
No, because they don't have a high enough level of silica.
Rising magma partially melts...
continental crust
Subduction accounts for what percent of erruptions of all magma?
In between the hot spots of volcanoes there are...
Hot spots are like
Huge giant like mountains underwater
What moves the plate or the hot spot?
The plate moves over the hot spot.
Does the composition of the oceanic and continental crust react the same or differently?
Differently because they are composed of different materials.
Who was Plutonic rock named after and why?
Pluto, the greek god of the underworld. These rocks are found deep burried in the earth, they cool slowly and create large crystals.
What magama sticky? Does this stickyness effect the way it errupts?
Silica makes magma sticky and if magma is sticky it is more likely to errupt.
Who were the Vulcanion Rocks named after and why?
Vulcan, the Roman god of fire. These rocks are found close to the surface of the earth, they cool quickly creating large crystals.
The solubility of volatiles of dissolving gases increases with increasing _________ and decreasing __________.
Pressure, Temperature
Viscosity is
the resistance to flow
The lower the viscosity the more...
fluid like it is
Water has a ________ viscosity.
Honey has a ______ viscosity.
The higher the temperature the __________ the viscosity.
The more silica a rock has the ____________ explosive it is.
The greater the content of SiO2 the __________ the viscosity.
Viscosity increases the ________ content of magma.
What percent of the earth's surface is basaltic rock?
As silicate increases, viscosity _____________ and temperature ____________.
Increases, Decreases
Why does the vast majority of Earth's magma pour out of spreading centers with ease.
Because the spreading centers sit above the hight temperature asthenosphere. The rock has a low percentage of SiO2 and the ocean plates pulling apart causes this hot asthenosphere rock to rise and experience lower pressure.
Why does the magma above subduction zones commonly explode violently?
When a subducting plate reaches a depth of 60 miles magma is generated and rises, the subducting plate carries sediments and water a hydrated mineral down with it.
What type of volcanos are more explosive?
Subduction zone volcanoes
Magma is generated by what three components?
1) Lowering pressure
2) Raising the temperature
3) Increasing the water content
Most magma is generated by what?
Decreasing the pressure of the hot rock.
What are three types of lava that come from non-explosive volcanoes?
Aa, pahoehoe, pillow
What are types of volcanic materical that come from explosive volcanoes?
Pyroclastics such as ash, cinders, blocks and bombs and glass such as obsidian and pumice.
What are the two eruption types of Shield volcanos?
Icelandic and Hawaiian
What type of erruption do cinder cones have?
What type of erruptions do composite voclanoes have?
Vulcanian and Plinian
What were the largest volcanic events on Earth? What did they produce?
Flood Basalts, produced an immense amount of mass an energy.
This is the largest of the explosive volcanoes and is formed by the collapse of the roof part of the volcano.
Examples of a caldera would be...
Crater Lake in Oregon, Krakataua and Santorini
An example of an Icelandic shield volcano would be...
Mauna Loa
An example of a Hawaiian shield volcano would be...this type of volcano is preceeded by what?
Haleakala on Maui, preceeded by earthquakes and creates a lava fountain which incinerates buildings and burys highways.
In Plinian type of eruption how does the volcano errupt?
The throat of the volcano is cleared by producing an incredible gas powered vertical eruption column.
In the Vulcanian type of eruption the volcano clears its throat and what follows this?
A larger erruption.
Stratovolcanoes or composite cones may what type of eruptions?
Vulcanian then Plinian then Caldera
In the Plinian type of eruption what do people suffocate from??
The gases produced
In the Plinian type of eruption what do people suffocate from??
The gases produced
What are lahars caused by? What are they good for?
Lahars are caused when water from the gases fall back to earth as heavy rain and mixes with the ash causing a volcanic mudflow. These lahars are good for agriculture.