How do we see inside the Earth? What do we use? __________________________ Seismology...
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Transcript of How do we see inside the Earth? What do we use? __________________________ Seismology...
How do we see inside the Earth?
• What do we use?• __________________________• Seismology• ____________________________• What do we know that produces
seismic waves?
P-waves
“P” or Primary waves– _______________– _______________– _______________ – Travel through all mediums ( solid, liquid
and air)
“S” Waves
• “S” or Secondary waves– _______________– Vibrate ____________/ ____________– _____________ than “P” waves– Only travel through _______________
The Crust• ________ __________• Like an eggshell• ___________• ___________• Can crack• Two regions:
– ______________ (Basalt rock)– ______________ (granite
rock)
• Crust is _______ dense than the mantle
• Like ice on water; the crust _____________ on the mantle
The Mantle
• _____________• Like the crust
– __________– __________
• Iron, magnesium, calcium are heavier elements
• Mantle is ________ dense • How does the Earth’s crust add to the
density of the mantle?• __________ ___________ down on the mantle…
it compresses the minerals, increasing the pressure and squeezing them into rocks.
Layers of The Mantle
• Upper mantle• ___________
– Rigid rock upper portion of upper mantle
• ___________– Lies beneath
lithosphere and “__________” like plastic
– It is ________…silly putty
• Lower mantle
The Core• ________ layers: inner and
outer core• ____ Earth’s volume• ____ Earth’s mass• 2x as dense as the Earth’s
mantle• Why?• Made of _____ ______• Inner core is VERY hot!• Some places as hot as the
surface of the sun!
The Inner Core• ______ ______
– How? – __________ from
Earth keeps Iron packed tightly; doesn’t allow it’s atoms to ______
The Outer Core
• Outer Core– _______ Iron– _______ pressure – _____ and _____ as Earth rotates– Creates _______ _________– Affects Earth’s ________– Produces _______ ______– Possibly responsible for Earth’s magnetic
field
Convection Currents
• What are convection currents?
• ________ of heat flows from ______ to ______
• This sets up a convection current in the ________
Effects of Convection Currents
• When the current comes at a weaker part of the ________, for example at a _______, ________ comes above the earth's surface.
• This is called ______ _______. • The movement of these plates goes very
slowly.• The _______ of two tectonic plates causes an
_________. • The ________ _______ along the bottom of the
_______ causes the moving of the tectonic plates.
Continental Drift & Tectonic Plates
• __________ Hypothesis on Continental Drift
• The World’s continents are in ________
• At one time, the continents were ______ together as one…
• This was known as _______• They fit together like a
jigsaw puzzle
Continental Drift
• Wegner’s theory proposed the landmass known as _______ started breaking up
• Separated into two parts: ______ and ________
• Wegner’s theory of the separation of Pangea was supported by ______, _________, _________ and _________ evidence
Seafloor Spreading• Seafloor is not _________• Constantly _________ itself• ____ ________ ______ (longest & tallest mountain range in the world, center
of the ________ Ocean)• Forms ________: Iceland and Azore• There are _______ in the mountains
Plate tectonics
• __________ move because they are _________ in plates
• The plates shuffle or move _____ of the Earth’s surface
• Plates move in _______ _______ and different ______ from each other
• There are ______ large plates and several smaller plates
Plate Boundaries
• _________ Boundaries– Plates move
_____from each other– Comes from rock in
the ______________– Partially melted– The rock partially
melts = _______– It was _____ before it
left the _______ of the Earth
Earthquakes
• Devastating• ______ (force) applied to _____• Stress causes ______• Eventually the rock cannot bend
anymore• It breaks and releases ______ ______• The released energy ( ______ _____)
travel out in all directions
Earthquakes cont• The initiating site of the
seismic wave: _______• The point at Earth’s
surface directly above the focus: ________
• Measured on a _______ _______ ( the increments are _____ fold in magnitude…)