Plate Movement Power Point
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Transcript Plate Movement Power Point
11/18/15
Earth’s
lithosphere is divided into
tectonic plates that move on top of
asthenosphere
Theory
of plate tectonics explains:
• Continental drift
• Sea-floor spreading
Convection
• Hot material from
deep within Earth
rises while cooler
material near surface
sinks
• Motion of convecting
mantle drags plates
sideways
Ridge
Push
• Occurs at mid-ocean
ridges
Higher elevation than
surrounding lithosphere
• Gravity causes the
ridge to “push”
oceanic plate down
the lithosphereasthenosphere
boundary
Slab
Pull
• Oceanic lithosphere
denser than
asthenosphere
• Oceanic plate sinks
and pulls rest of
tectonic plate with it
Occurs because of
process of subduction
Occurs
when two
plates push into one
another
Three
types (depends
on plates involved)
• Continental/continental
• Continental/oceanic
• Oceanic/oceanic
Occurs
when two
tectonic plates move
away from one
another
Results
in new
oceanic lithosphere
(sea-floor spreading)
Can
also be found on
continents
East African Rift
Occurs
when two
tectonic plates slide
past each other
horizontally
Plates
grind past one
another often
resulting in
earthquakes
• Tectonic plates are not
San Andreas Fault
smooth
Movement
affected by:
• Type of plate
Measure
motion by
use of GPS
• Shape of plate
• Interaction with
surrounding plates
Generally
slow (few
centimeters per year)
• San Andreas fault is
exception
“Stationary” GPS
satellites send
signals to ground
stations
• Amount of time taken
to receive signal in
relation to distance
determines rate