Earth Layers/Plate Tectonics/Seismic Activity Flashcards
What are the layers of the earth in order?
Crust, mantle, outer core, inner core
What is the continental crust mostly made of?
Granite
Which is thicker, the continental crust or the oceanic crust?
Continental crust
How much of the earth’s surface does the continental crust make up?
25%
What is the oceanic crust made of?
Basalt
How much of the earth’s surface does the oceanic crust make up?
75%
What is the thickest layer of the earth?
The mantle
How much of earths volume is the mantle?
82%
The upper mantle is part of what?
The lithosphere
Where is the athenosphere located?
The middle mantle
How many miles thick is the outer core?
1400 miles
What is the outer core made of?
Nickel and iron
The flow of the inner core creates earths ________ field
Magnetic
The inner core of the earth has extremely high _____ and _____
Temperatures and pressure
The inner core is made of
Nickel and iron
The inner core makes up how much of the earths mass?
1/3
What are plate tectonics?
The earths crust is made of 12 different plates moved in various directions
Tectonic plates are made of what?
The lithosphere
The plates of lithosphere are moved around by the underlying hot mantle convection cells in the ______
Athenosphere
In what 3 ways do tectonic plates move? 
Divergent, convergent and transform plate boundaries
Divergent plates move away or towards each other?
Away
Example of divergent plate boundary?
Iceland
Convergent plate boundaries move away or towards each other?
Toward
Example of a convergent boundary?
Cascade mountains
Transform plate boundaries move how?
They move past each other
Example of a transform plate boundary 
San Andreas Fault
What are subduction zones?
When the oceanic crust sinks into the mantle beneath continental crust melting the rock
What are earthquakes?
When two blocks of the earth suddenly slip past one another
What causes earthquakes
When tectonic plates slip past one another
What is the Fault?
The surface where the tectonic plates move past each other
What is the hypocenter?
The location BELOW the earths surface where the earthquake starts
What is the epicenter?
The location directly above where the earthquake happens ON the surface of the earth
What are foreshocks?
Smaller earthquakes that happen BEFORE the larger earthquake
What are aftershocks?
Smaller earthquakes that happen AFTER the main shock
What is the main shock?
The largest, main earthquake
What is a tsunami?
A sea wave that is formed when large amounts of sea floor move
What causes a tsunami?
Water displacement such as earthquakes, volcanic eruptions, or landslides
What are the signs of a tsunami?
Hard ground shaking, a sudden sea level withdrawal, or they can cause loud booming noises.
How big are tsunamis?
Over a hundred feet to 1,720 feet high
Is a tsunami in a rogue, wave the same thing? 
No
What is a mega tsunami? 
A very large wave created by a large sudden displacement of material into a body of water
What is a volcano?
A vent or opening in the earths surface which molten rock, gasses and ash erupt
How are volcanoes formed? 
When magma works its way to the surface and erupts to form lava flows and ash deposits
What are the different stages of volcanoes? 
Active, dormant, and extinct
Example of an active volcano
Mount Vesuvius in Italy
Example of a dormant volcano
Mount Fuji in Japan
Why do volcanoes erupt? 
When gas bubbles inside magma expand and cause pressure to build up
What are cinder cones?
Circular oval cones made up of small fragments of lava from a single vent that have been blown into the air
What are composite volcanoes?
Steep sized volcanoes composed of many layers of volcanic rock
What is an example of a cinder cone?
Paricutin
What is an example of a composite volcano?
Mount Rainier
What are shield volcanoes?
Shaped like a bowl or shield in the middle with long gentle slopes
Example of a shield volcano?
Mount Kilauea
What is Lahar?
Type of mudflow composed of pyroclastic material, rocky debris and water.
Why is Lahar so dangerous? 
Because it is liquid and when it stops moving it solidifies
