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Flashcards in The Earth's Structure Deck (10):

What components make up the earth's structure?

Crust, mantle, outer and inner core


Describe the crust

The bit we live on, is very thin (5 km and 50 km) and is surrounded by the atmosphere


Describe the mantle

Below the crust is the mantle. The mantle has all the properties of a solid, except that it can flow very slowly
Within the mantle, radioactive decay takes place. This produces a lot of heat, which causes the mantle to flow in convection currents


Describe the core

It's at the centre of the earth, which we think is made of iron and nickel


What is the earth's surface made up of? (short)

tectonic plates


Describe tectonic plates

The crust ad the upper part of the mantle are cracked into a number of large pieces.
The plates don't stay in one place though. That's because thee convection currents in the mantle cause the plates to drift


What speed are most of the plates moving at?

A few cm per year relative to eachother


What causes an earthquake? (Short)

Plates moving very suddenly


Where do volcanoes and earthquakes occur?

At boundaries between 2 tectonic plates


What clue is there for volcanoes erupting soon?

Before an eruption, molten rock rises up into chambers near the surface, causing the ground surface to bulge slightly. This causes mini-earthquakes near the volcano
However sometimes the molten rock can cool down