Chapter 4 - The Earth's Surface: Shaping the Crust Flashcards
What is the Crust?
The Crust is the outside layer and is made of solid rock
What is the Mantle?
The Mantle lies under the Earth’s Crust and is made from Molten/Semi-Molten rock called magma
What is the Core?
The Core is the Centre of the Earth. It is made from iron and nickel
What is the Crust made up of?
The crust is made of Oceanic and Continental Plates.
What is the point where plates meet?
A Boundary
What is a Convection Current?
A Convection Current is how the plates move. The magma in the mantle heats up, and rises up towards the crust. It then cools, and flows down towards the core. This causes the plates to move.
What is the movement of the plates called?
Continental Drift
What is the Study of the Plates called?
Plate Tectonics
Can you name 3 Plates?
North American Plate Eurasian Plate African Plate Nazca Plate Pacific Plate South American Plate Antarctic Plate Indo-Australian Plate
What were the continents called 225 million years ago?
Pangea
What happens at each of the Boundaries?
Plates collide [Destructive Boundaries] Plates Separate [Constructive Boundaries] Plates slide past each other [Passive Boundaries]
Where does volcanic activity occur? And name an example of where!
Volcanic Activity occurs where plate separate and collide [Pacific Ring of Fire]
What country is made up of volcanos?
Iceland
Explain what a Mid-Atlantic Ridge is.
A Mid-Atlantic Ridge is made when magma rises up through fissures,hardens, and forms new land in the ocean.
Briefly explain a Volcano!
Magma Chamber: Where magma is in the mantle.
Vent: Where the magma rises up through [Narrow Vent]
When it reaches the surface it is know as lava. Ash and hot rocks are thrown into the air and an ash cloud is formed. There is a build up of material around the vent, forming a cone shape. The top of the volcano is called the crater.
Explain the 3 types of volcano.
Active: These volcanoes erupt regularly
Dormant: These have not erupted for a long time, but could possibly erupt again
Extinct:These volcanoes have not erupted in recorded history.
what are the positive effects of a volcano?
The soils around the volcano are rich in minerals.
Tourists can visit the sites od famous volcanoes.
Hot springs called geysers are formed.
Volcanoes create new land.
What are the Negative Effects of Volcanoes?
Gases, such a sulphur dioxide, can poison people and cause acid rain.
Lava flow burns everything in it’s past.
Loss of human life.
Lahar can be formed when snow mixes with lava.
What are Earthquakes?
Earthquakes are sudden tremors or vibrations in the Earth’s Crust.
How does an Earthquake form?
An earthquake forms when two plates attempt to slide past each other, and build up pressure.
Briefly explain an Earthquake.
Earths occur when there is pressure along the fault line.The point beneath the surface where the earthquake happens is called the focus. The point above the focus is called the Epicentre.
Where are the tremors strongest during an Earthquake?
The Epicentre. The further away from the Epicentre, the less amount of strength. The smaller tremors that follow an earthquake are called aftershocks.
Who is a person that studies Earthquakes, and what do they use?
A Seismologist. They use instruments called seismographs to measure the tremors in the earths crust.
What is used to measure the strength of an earthquake?
The Richter Scale.
What damage can be caused by earthquakes?
Loss of life. Buildings are damaged Damage to electricity and gas supplies may cause fires. Bridges,Roads and railway lines are damaged. Landslides and avalanches are TRIGGERED. Damage to sewers and Water Supplies Earthquakes can cause Tsunamis.
How could we reduce the damage caused by earthquakes?
Build earthquake-resitant buildings in earthquake zones.
Study the pattern of past earthquakes to try to predict when the next one might occur.
What are Fold Mountains?
Fold mountains forms when 2 plates collide with each other
What is an up-fold?
Anticline
What is a down-fold?
Syncline
