Natural Hazards Flashcards
(22 cards)
What are natural hazards?
Events like earthquakes, volcanoes or floods that pose a threat to people and the environment.
What are the 4 layers of the Earth?
Crust, mantle, outer core and inner core.
What is the outer core and inner core made of?
Iron and nickel
Is the outer core solid or liquid?
Liquid
Is the inner core solid or liquid?
Solid
What is continental drift?
The gradual movement of the continents across the Earth’s surface through geological time.
Who made the theory of continental drift?
Alfred Wegener
What are 3 pieces of evidence that prove Wegener’s theory?
The continents fit together like a jigsaw and similar rock and fossil patterns were found on both sides of the Atlantic.
What was the name for when all the continents were merged?
Pangea
Why did it take 50 years for Wegener’s theory to be accepted?
As it was difficult to understand how whole continents could move.
What are the steps to convection currents?
1- Heat is generated from the Earth’s core
2- This heat rises through the mantle
3- This creates magma which pulls the plates apart
4- Afterwards, the magma cools and sinks.
What is a plate boundary?
The edge of a plate/ where 2 plates meet.
What are the 4 different plate boundaries?
Conservative, constructive, collision and destructive.
Describe a conservative plate boundary.
Where two plates are rubbing against each other causing friction and creates earthquakes.
Describe a constructive plate boundary.
Where 2 plates are moving away from each other by convection currents causing magma to rise to the surface. This creates small earthquakes and volcanoes.
Describe a collision plate boundary.
Where convection currents push the plates together causing them to crumple and uplift. This creates fold mountains.
Describe a destructive plate boundary.
When oceanic and continental plates towards eachother. The oceanic plate is sub-ducted leading to melting of the plate causing volcanic eruptions/earthquakes.
What are the 7 main plates?
The Pacific, South American, North American, Eurasian, African, Antarctic and Indo-Australian Plate.
What plate is the Ring of Fire located around?
The Pacific plate
What are the 8 different parts of a volcano?
Ash cloud, Pyroclastic flow, lava flow, crater, main vent, magma chamber, secondary vent and cone.
Why might someone want to live near a volcano?
As volcanic rock and ash provide fertile land which results in a higher crop field for farmers. Also, volcanoes gain many tourists which would increase the money to the local economy.
What are the negative consequences of living near a volcano? Specify about tephra falls or lahars.
Tephra falls- their ash deposits can damage buildings, disrupt transportation and cause respiratory problems.
Lahars- their volcanic mudflows can engulf villages and bury communities.
