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19 Cards in this Set

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How many people died from the Mt. St. Helens eruption?
57
What is "Dome Forming"?
The attempt of the volcano to rebuild itself.
How tall was the peak of Mt. St. Helens before it erupted compared to after?
5th tallest peak in the state of Washington before eruption, now the 37th.
What happens during a Phreatic Eruption (crater)?
Hot ash meets water.
What determines the type of eruption that will occur in a volcano?
Magma
What kind of lava only forms under water?
Pillow Lave
The Earth is _____ miles or _____ kilometers around the equator.
25,000 miles or 40,000 kilometers (40k).
How long would it take to walk all the way around the equator?
6.2 school years
How old is the Earth?
4.6 billion years old
Who must create/enact a national park?
(act of) Congress
Who establishes a national monument, and who must approve it?
The President can establish a national monument, and Congress must approve it.
When it comes to national parks, who is the department of interior, and who is in charge of the operations?
The NPS is the department of interior, and the superintendent is in charge of the operations.
What units are used in the geologic time scale?
Eras, Periods, and Epochs.
What is the Precambrian Era, and what is it divided into on the geologic scale?
The Precambrian Era is the name for the span of time before the Phanerozoic eon (now), and is divided into eons on the geologic scale.
What are epochs?
An instant in time chosen as the origin of a particular era; serves as a reference point from which time is measured.
What material exists in ALL magma?
Silica
What is lava viscosity?
Resistance to flow
Where is basalt generally located?
Andesite?
Rhyolite?
1. ocean floor, divergent plate boundaries, lava plateaus
2. convergent plate boundaries, ocean continent subduction zones
3. convergent plate boundaries and hot spots
Which of the rocks from cooled lava have the least, intermediate, and greatest amount of silica in them?
Basalt=least (basic)
Andesite=intermediate
Rhyolite=greatest (acidic)