Tectonic Plates Flashcards
Name 8 major tectonic plates
North American, Eurasian, African, Indian, Pacific, Nazca, Australian.
Facts about the Inner Core
Solid
5000’c
1270km
Iron and Nickel
Facts about the Outer Core
Liquid
4000’c
2200km
Iron and Nickel
Facts about the Mantle
Liquid
1600’c
2900km
Peridite
Facts about the Oceanic Crust
Solid Made of Basalt Sima (Silica and Magnesium) More dense 0-100km
Facts about the Continental Crust
Solid Made of Granite Sial (Silica and Aluminium) Less dense 0-100km
In what year did Alfred Wegener propose the idea of Continental drift?
1912
What is the evidence for Continental drift?
1) Jigsaw fitting coastlines
2) Same rock sequences in different countries
3) Coal beneath Antarctica (would’ve been at a lower latitude)
4) Matching fossils in different continents (Permian fossils called Mesosaqurus found in SW Africa and Brazil)
5) Glacial deposits and striations in Brazil math those in W Africa
In what year did Harry Hess prove Wegener’s theory?
1962
How did Harry Hess prove the theory of Continental Drift? (With Sea Floor Spreading)
By using Carbon Dating
- He was able to recognise the newest rock formed on the Atlantic Floor was formed in the centre.
Natural Event
When an event happens however no people are affected (the middle of the dessert)
Natural Hazard
When an event takes place and people are affected
What is the disaster crunch model?
A model that demonstrates that a disaster is the intersection of 2 processes( The natural hazard and the vulnerability generated)
Oceanic/Oceanic Constructive(Divergent) Margin
-Oceanic plates more away from each other.
Formations (Shield volcano(submarine volcanos), Oceanic Ridge, Shallow earthquakes)
-EXAMPLE(Mid Atlantic Ridge)
Continental/Continental Constructive(Divergent) Margin
-Continental plates move away from each other.
Formations (Rift Valley)
EXAMPLE(The Great African rift Valley)
Oceanic/Oceanic Destructive(Convergent) Margin
-Oceanic plates move towards each other
Formation (Oceanic trench, Earthquakes, Island Arcs, Shield volcano)
EXAMPLE(Marianas Trench)
Continental/Continental Destructive(Convergent) Margin
-Continental plates move towards each other
Formations (fold mountain ranges, Shallow focus earthquakes)
EXAMPLE(Himalayas)
Oceanic/Continental Destructive(Convergent) Margin
-The 2 plates move towards each other
Formations (Oceanic trench,Fold mountain range, Composite cone volcano, deep earthquakes)
EXAMPLE(Peru-Chile trench/Mt St Helens)
Conservative Margin
-The 2 plates move past each other (in different directions/same direction BUT different speeds)
Formations (Earthquakes)
EXAMPLE(San Andreas vault)
How long has the Hawaiian Ridge-Emperor Seamounts been built?
70million years
What is a hot spot?
An area of slightly more energy in the core, causing the magma to rise and burst through the crust, the spot remains stationary but the tectonic plates above move over it, resulting in a trial of active and dormant volcanoes
Where was the highest recorded earthquake?
Chile, 9.5
Which earthquakes are more dangerous?
Shallow
Deep earthquakes seismic waves are absorbed more by rocks and the crust
On average how many major earthquakes occur each year?
3-4
