Geography Y09 Aut1 Flashcards
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Plate Tectonics
Theory of Earth’s structure and causes of earthquakes and volcanoes
natural hazard
A natural event that poses a risk to human life.
crust
The thinnest layer of the Earth that we consider the ‘surface’.
mantle
The layer underneath the crust containing liquid rock.
core
The centre layer of the Earth that is solid rock.
magma
Liquid rock found in the mantle.
convection currents
currents driving moving magma in the mantle.
continental drift
The theory of plate tectonics moving around the Earth’s surface.
lava
Liquid rock pushes through the Earth’s crust in an eruption.
volcano
Lava pushes through the Earth’s crust in an eruption.
earthquake
The shaking of the Earth’s crust.
tsunami
Harbour wave – a large wave created by an underwater earthquake.
focus
The centre of the earthquake underground.
epicentre
The centre of the earthquake found on the crust.
seismometer
An instrument used to measure the power of an earthquake.
magnitude
The power of an earthquake.
Richter scale
Measures the magnitude of an earthquake.
Mercalli scale
Measure the destruction level of an earthquake.
plate margin
The border where two tectonic plates meet.
destructive plate margin
When one plate pushes under another, into the mantle. E.g. Nazca plate and South American.
constructive plate margin
When two plates pull apart from each other, making new land. E.g. North American and Eurasian plates.
collision plate margin
Two plates hit each other, and land is forced upwards to form mountains E.g. Indian and Eurasian plates.
conservative plate margin
Two plates slide past each other. No land is destroyed or created, E.g. North American and Pacific plates.
pyroclastic flows
A mixture fast-moving of gas and lava
adaptation
Teaching people how to live with the risk of volcanoes and earthquakes.
mitigation
The act of protecting people from the effects of volcanoes and earthquakes.
