Transcript Restless Earth

Restless Earth
By Benji Johnson, Ben Joy,
Callum Barber and Philip
Carr
Structure Of the Earth
•Made up of distinct layers,
like onion
•The solid crust has
relatively low density, sits
and moves on top of mantle.
•The crust is thin compared
to the diameter of the planet.
•The crust is made up of
sections called plates, which
vary in size.
•Continental crust is much
thicker than oceanic, but is
less dense.
Plate Tectonics
Plate Boundaries
Constructive Boundaries
Conservative Boundaries
Destructive Boundaries
Collision Boundaries
Volcanoes and Earthquakes
Examples of Volcanoes and
Earthquakes
Earthquakes
How do they occur?
• Formed when plates get stuck due to
friction and then slip releasing energy
Earthquakes
Kashmir 2005
Richter scale-7.6
Earthquakes
Loma Prieta 1989
Richter scale-6.9
Famous Earthquakes
Japan 2011 – 8.9 magnitude on
Richter Scale
How ready is San Francisco?
• SF Will be hit, in the next few years, by the Big One.
• An earthquake three times more powerful than Loma
Prieta.
• lies on the San Andreas Fault where big, sudden
movements occur
• Although firefighters and police train
regularly, everything is not ready.
• The bridges and hospital may not be
able to cope with the earthquake.
• Scientists say that there is a 2 in 3
chance of a “Big One” by 2032.
Volcanoes
Volcanoes – What are they?
• Formed at destructive or constructive plate margins
• Erupt lava
• Large mountains
How are they formed?
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Destructive boundaries
Subduction occurs
Material melts into molten magma of mantle
Weak crust melted away
Surface volcano formed
Constructive boundaries
Plates move apart
Ocean trench made
Magma comes through
Seabed volcano formed
Why do they erupt?
• Tectonic activity
• Magma under high pressure
• Pressure released, lava erupts from volcano
• Like shaking a fizzy drink and opening it
Types of volcano
Shield
Composite
Super
Where are the Earth’s volcanoes?
States of volcanoes
Active
Dormant
Extinct
Volcanoes
Laki 1783-84
Volcanoes
Montserrat 1995
QUIZ
1) What two metals is the core
mostly made up of ?
2) What tectonic plate are we on ?
3) Give an example of the hotspot
theory
4) What is the largest volcano on
Earth?
5) What was the magnitude of the
Kashmir, 2005 earthquake?
6) What sort of magma is formed at
destructive margins?
7) In what year did Mount Pinatubo
erupt?
8) Name 5 objects that you would
have in an emergency earthquake
pack
9) What is the global distribution of
volcanoes called?
10) What are the three states of
volcanoes
Thanks for listening.