Geography: Tectonics Flashcards
What are the four main layers of the Earth?
The inner core
The outer core
The mantle
The crust
Describe the inner core.
The inner core is extremely hot and is a very dense solid.
Describe the outer core.
The outer core is 2,000 km thick and is a liquid.
Describe the mantle.
The mantle is semi-molten and about 3,000 km thick.
Describe the crust.
The crust is the rocky outer layer; it is approximately 5-70 km thick.
What is a plate margin?
Where two or more plates meet .
What are convection currents?
Movement within the Earth’s mantle caused by the heat of the core.
When does a constructive plate margin occur?
When plates move apart.
What natural hazards occur at constructive plate margins?
Volcanoes and earthquakes.
What examples of constructive plate margins are there?
The North American and Eurasian plates which formed the mid-Atlantic Ridge
When does a destructive plate margin occur?
When tectonic plates move towards each other and collide.
What are the effects when two continental (land) plates collide on a destructive plate margin?
Compression forces form fold mountains.
What are examples of two continental plates colliding on a destructive plate margin?
The Indian and Eurasian plates which formed the Himalayas.
What are the effects when an oceanic and continental plate move towards each other on a destructive plate margin?
The denser oceanic plate is subjected and sinks under the continental plate. Earthquakes, fold mountains and volcanoes occur.
What is an example of oceanic and continental plate moving towards each other on a destructive plate margin?
The Nazca and South American plates.
When does a conservative plate margin occur?
When plates slide past each other.
What are the effects of a conservative plate margin?
Earthquakes occur.
What is an example of a conservative plate margin?
The North Atlantic and Pacific plates forming the San Andreas Fault.
Name two characteristics of a shield volcano.
Gently sloping sides, runny lava.
Name two characteristics of a composite volcano.
Steep sided and cone-shaped, sticky lava.
What are the three types of hazard and their definition?
Atmospheric - Related to weather
Geomorphological - Related to mass movement/ gravity acting on land
Tectonic - Related to movements of the earth’s crust
What are earthquakes?
The sudden violent shaking of the ground.
What is the focus of an earthquake?
The point inside the Earth’s crust where the earthquake originates.
What is the earthquake’s energy released in?
Seismic waves.
