Transcript Earth`s interior volc eq3

Where Volcanoes Form
• Mid-Ocean Ridges
– Lava flows out to make crust
– Where most volcanic activity takes
place
• Convergent boundaries
– During subduction, the
temperature and pressure increase
causing lava to form
Where Volcanoes
Form
• Hot spots
– Not along boundaries
– Above columns of rising
magma, results of cracks in
the crust
– Ex. Hawaiian Islands or
yellowstone (one of the
worlds largest!!)
Predicting
Eruptions
• Dormant and Active (not
extinct)
• Monitoring earthquakes
• Studying volume and
composition of volcanic
gases
• Measuring temperature
Goop!
Solid when pressure / movement = walk on it
Liquid when no pressure / movement = sink
https://www.youtube.com/watch?v=f2XQ97XHjVw
Tectonic Plates
Earth’s crust consists of major and minor
tectonic plates that move relative to
each other.
A Giant Jigsaw Puzzle
• The lithosphere is
made of plates
that fit together
like a puzzle.
• Vary in size and
thickness.
• Float on the
asthenosphere
like ice floats in
water.
Wegener’s Continental Drift
Hypothesis
• Early 1900’s by Alfred
Wegener. Accepted in
the 1960s (not that long
ago!)
• Continental drift continents once formed
a single landmass,
broke up, and drifted to
their present locations.
• Pangaea existed about
245 million years ago.
• Evidence is fossil records
Tectonic Plate Boundaries
• Three types
– Convergent
• plates collide
• Destroyed crust!
– Divergent:
• plates separate
• Growing crust!
– mid-ocean ridges
– Transform:
• plates slide
horizontally past
each other
– San Andreas Fault
– Earthquakes!!