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Where would you find an ocean trench?
Along destructive plate margins where the oceanic crust is pushed under the continental crust, which is known as subduction.
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Describe the shape of a supervolcano
-Have steep mountain ridges around them. -Have large depressions called calderas.
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Describe the size of a supervolcano
-Mega volcano that erupts upto 1000km of material (Magma escaping). -Very wide (70-80km)
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How are ridges and shield volcanos formed?
By the build up of magma
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The difference between composite volcanos (occur on destructive plate margins) and shield volcanoes (occur on constructive plate margins)
COMPOSITE: -Eruptions can be explosive/violent. -Can be dormant for long periods. SHIELD: -Non-explosive eruptions as lava flows freely. -Eruptions are frequent
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Composite Volcanos shape
Steep slopes and narrow base
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Sheild volcanos
Wide base and gentle slopes
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Focus
Where the earthquake starts underground
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Epicentre
The point on the earths surface vertically above the focus of an earthquake
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The 4 layers of the earth
-Inner core (Solid iron and nickel:over 5000 degrees) -Outer core (Liquid iron and nickel) -Mantle (Molten rock: moving 1800-3500 degrees) -Crust (Thinnest layer)
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2 landforms found at plate boundries
-Ocean trenches. -Young fold mountains (Both occur at destructive plate margins)
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Define subduction
The sinking of oceanic crust at a destructive margin
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2 differences between continental crust and oceanic crust
Oceanic is denser at 5-10km, which is thinner than continental which is 20-80km thick and less dense
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Example of a constructive plate margin
-South American Plates. -Atlantic Plates
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Example of a destructive plate margin
-Nazca Plates. -South American Plates
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Example of a conservative plate margin
-North American Plates. -Pacific Plates
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What is the richter scale?
The strength of an earthquake is usually measured given according to the richter scale. Measured using a seismograph as the earthquake happens.
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What is the mercalli scale?
Measured using scientific observations after the earthquake has happened. It uses roman numerals on a scale of 1-12. It measures the power and effects of he earthquake
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Name 3 tectonic plates
-North american plate, pacific plate, south american plates, etc
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What happens at conservative plate boundaries?
Plates slide past eachother. Sometimes the plates are going in the same direction but at different speeds
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What happens at constructive plate boundaries?
Plates move apart and magma rises to fill the gap. New crust is formed. Usually found under the sea.
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What happens at destructive plate boundaries?
Plates move together, and one plate slides under the other. The lighter continental crust stays on top while the denser oceanic crust is pushed down into the mantle where it melts
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The formation of young fold mountains
1st, thick sediment layers form in huge depressions called geosynclines under the sea. Over millions of years, the sediment are compressed into rock. The sedimentary rocks are forced into folds as the plates move
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2 characteristics of oceanic crust
-Newer, most are less than 200 million years old. -Denser and can sink
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2 characteristics of continental crust
-Older, most are over 1500 million years old. -Less dense and cannot sink
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How are ocean trenches formed?
Formed in the subduction zone of a destructive plate margin. One wall of the trench is formed by the other subducting oceanic crust. The other wall is the edge of the continental crust.
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Explain how tectonic plates move
The heat from the earths core created convection currents in the mantle. This hot molten rock rises moving the plates on the surface which form the crust.
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How was the himalayas formed?
By a continental collision eg; india and asia forming the himalayas which is the worlds biggest mountain range
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Other cards in this set

Card 2

Front

-Have steep mountain ridges around them. -Have large depressions called calderas.

Back

Describe the shape of a supervolcano

Card 3

Front

-Mega volcano that erupts upto 1000km of material (Magma escaping). -Very wide (70-80km)

Back

Preview of the back of card 3

Card 4

Front

By the build up of magma

Back

Preview of the back of card 4

Card 5

Front

COMPOSITE: -Eruptions can be explosive/violent. -Can be dormant for long periods. SHIELD: -Non-explosive eruptions as lava flows freely. -Eruptions are frequent

Back

Preview of the back of card 5
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