Download Year 8: Tectonics: Revision worksheet SS2017 1. Constructive plate

Year 8: Tectonics: Revision worksheet
Inner Core
Outer Core
Mantle
Crust
Tsunamis are tidal waves triggered by underwater
earthquakes. The rate of travel of a tsunami is between
400- 600 miles per hour. They usually occur at destructive
plate margins. The tsunami in SE Asia occurred on the 26th
Conservative
Collision
Destructive
December 2004. The earthquake measured 9.0 on the
Richter Scale and occurred off the northern tip of Sumatra.
The tsunami spread across the Indian Ocean and hit coastal
Constructive
areas of Sri Lanka, India, Bangladesh, Myanmar, Indonesia
and Malaysia. The death toll is believed to be 290,000.
1. Constructive plate margin
At a constructive plate boundary, two plates move apart. As the two plates move apart, magma
rises up to fill the gap. This causes volcanoes. However, since the magma can escape easily at
the surface the volcano does not erupt with much force.
2. Destructive plate margin
A destructive plate boundary is found where a continental plate meets an oceanic plate.
The oceanic plate descends under the continental plate because it is denser. As the plate
descends it starts to melt due to the friction caused by the movement between the plates. This
melted plate is now hot, liquid rock (magma). The magma rises through the gaps in the
continental plate. If it reaches the surface, the liquid rock forms a volcano.
3. Collision plate margin
Collision boundaries occur when two plates of similar densities move together (i.e. a continental
plate and a continental plate). This causes the material between them to buckle and rise up,
forming fold mountains.
SS2017
Year 8: Tectonics: Revision worksheet
4. Conservative plate margin
Conservative plate boundaries exist where two plates do not directly collide but slide past each
other along a fault (weakness). No volcanoes are found along these plate boundaries, but
earthquakes do occur. An example of such a boundary is the San Andreas Fault in California.
7
8
5
5
3
1
2
6
4
1. Nazca 2. South American 3. African 4. Antarctican 5. Pacific
6. Indo-Australian 7. Eurasian 8. North American
Roof timber
bolted to walls
Steel
bracings
Emergency
escape
stairs
Emergency water
supply
SS2017
Basement reinforced
to prevent collapse
Shatter
proof
windows
Joists bolted to
frame
Automatic cutoff valves for
gas pipes
Emergency bin
(and water)
Deep foundations
Year 8: Tectonics: Revision worksheet
What is Continental Drift?
Do all volcanoes erupt?
In 1912, a German scientist called Alfred
* Active volcano – liable to erupt e.g. Mt
Wegener proposed that South America and Africa
Etna.
were once joined together and had thus moved
apart.
* Dormant (sleeping) volcano – a volcano
which has not erupted for many years. For
He believed that all the continents were once
example, Mt Pinatubo erupted in 1991 after
joined together as one big land mass called
500 years of dormancy.
Pangaea until about 200 million years ago.
Evidence for Continental Drift:
* Pattern of rocks
* Shapes of continents
* Extinct volcano – a volcano which has not
erupted for many thousands or millions of
years e.g. Edinburgh.
Types of volcano:
* Study of fossils
Cone
Shield
SS2017
Composite
Year 8: Tectonics: Revision worksheet
Advantages of living in volcanic
Disadvantages of living in volcanic
areas:
areas:
* Fertile soils * Minerals * Tourism
* Toxic gases * Fire * Disease
* New land * Heat for electricity
* Crops destroyed * Illness/death
Useful links:
http://www.bbc.co.uk/schools/gcsebitesize/geography/natural_hazards/
https://www.youtube.com/watch?v=mpMXEPN2EeA
Notes:
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
_______________________________________________________________________
SS2017