Our Restless Planet - Half Term 1 Flashcards
Define ‘hazard’
A naturally occurring or human produced occurrance that has the potential to cause damage
Define ‘disaster’
An event when people experience severe damage or disruption to their lives as a consequence of a hazard
What is the innermost layer of the earth called?
Inner core
What is the second-innermost layer of the Earth called?
Outer core
What is the second-outermost layer of the Earth called?
Mantle
What is the outermost layer of the Earth called?
Crust
Define ‘tectonic plate’
Tectonic plates are pieces of the Earth’s crust which make up the Earth’s surface
Define ‘plate boundary’ (also known as plate margin)
The point where two plates meet
Define ‘earthquake’
A sudden violent shaking of the ground caused by the passage of seismic waves through the Earth
Define ‘volcano’
An opening in a planet or moon’s curst through which molten rock, hot gases, or other materials erupt
What is the oceanic crust made of?
Silicon and magnesium
What is the continental crust made up of?
Silicon and aliminium (NOT aluminum)
The rock closest to the boundary is (oldest/newest)
Newest
What does subducting mean?
Sinking
How do fold mountains form?
Plates converge. Due to the two plates being the same weight, they both go up. (e.g. Himalayas)
What is a destructive margin?
An area on Earth where two or more tectonic plates collide (e.g. Pacific and Eurasian plate)
What is a constructive margin?
An area on Earth where two or more tectonic plates move apart (e.g. Mid-Atlantic ridge)
Why does a volcano erupt in a constructive margin?
- The upper mantle melts
- It rises through the gap formed by the tectonic plates because hot things rise
What is a conservative plate margin?
An area on Earth where two or more tectonic plates slide past each other, where no new rock is created or destroyed
What are some hazards of a constructive margin?
- Earthquakes
- Eruptions
Why does some rock subduct in a destructive margin?
One of the plates subducts because it is heavier, therefore it sinks.
Why does a volcano erupt in a destructive margin?
- Gases and magma can’t escape due to there being no gap
- Pressure builds up
- More explosive than constructive margin
Why do plates move?
Ridge push
Define ‘focus’ (in the context of an earthquake)
The point in the Earth’s crust where the earthquake forms
Define ‘epicentre’
The point where the earthquake huts the Earth’s surface, directly above the focus
Define ‘seismic waves’
Currents of energy that travel though the Earth
What are the steps for an earthquake?
- Plates move
- Plates get stuck
- Pressure builds up
- Plates stop + pressure is released
- Earthquake occurs
