Tectonics, Structure Of The Earth and Tsunamis Flashcards
What is oceanic crust mainly made of?
Basalt
Which plate is thin but heavy and dense?
Oceanic plates
What is the thickest layer of the earth?
The mantle (2,900km)
What causes earthquakes and volcanoes?
The movement along the edges of the plates
What is a constructive plate boundary? Give an example
A constructive plate boundary occurs when plates move apart. This causes volcanoes to be formed as magma wells up to fill the gap, and eventually new crust is formed.
An example of a constructive plate boundary is the mid-Atlantic Ridge.
Give three facts about the inner core
It is made up of Iron and nickel, is solid and is the hottest part of the earth.
What is the outer layer of the earth?
The crust
Give three facts about the crust
It is thin, forms the ground we live on and is divided into several large pieces called plates
Give three facts about continental plates
They are thick, old, and generally contain light rocks that are less dense, e.g granite
What causes plates to move?
Convection currents
What is a destructive plate boundary? Give an example.
When an oceanic and continental plate move together. The oceanic plate is forced underneath the lighter continental plate, creating an oceanic trench
An example is when the Nazca plate is forced underneath the South American plate.
Give three facts about oceanic plates
They are thin, young and generally contain heavy rocks that are more dense e,g basalt
How can volcanoes be monitored?
Thermal imaging techniques and satellite cameras can be used to detect heat around a volcano.
Describe three things about the outer core
It is 1,200km deep, liquid and has similar temperatures to the inner core
What is the Ring of Fire?
The Ring of Fire is a large basin area in the Pacific Ocean where lots of volcanoes and earthquakes occur.
What are the plates of the earth?
The plates are the sub-layers of the earths crust that cause earthquakes, volcanoes mountains and oceanic trenches.
What are plate boundaries/plate margins?
The edges of plates
How do volcanoes erupt?
Magma rises through cracks in the Earth’s crust, and when this pressure is released magma explodes to the surface causing a volcanic eruption.
Where do most earthquakes and volcanoes occur?
Earthquakes and volcanoes are most likely to occur either on or near plate boundaries
Name the two types of plate:
Oceanic plate
Continental plate
What are collision zones?
Collision zones are when two continental plates collide, neither of which go beneath each other, so they are forced upwards to create fold mountains.
What are convection currents?
Convection currents are the movement within the earths mantle caused by the heat of the core. The mantle is very hot.
What is the centre of the earth called?
The inner and outer core
What is a conservative plate boundary? Give an example
A conservative plate boundary occurs when plates slide past each other in opposite directions. Friction gradually builds up and the plates slip past in a sudden movement. The shockwaves created produce an earthquake.
This occurs at the San Andreas Fault in California.
