Plate Tectonics Flashcards
What are the 4 layers of the earth called?
Crust-solid
Mantle-semi fluid
Outer core-liquid
Inner core-solid
What is the crusts characteristics?
The earths solid crust is broken into huge moving slabs called tectonic plates
What is the mantle characteristics?
Surrounding the outer core and it is made up of Molton rock, 3000km deep
What is the cores characteristics?
The solid inner core is surrounded by the liquid outer core
What is a plate?
A huge slab of crust
What is a convection current?
Energy trapped during nuclear explosions in the core create vast amounts of heat and as this heat tries to escape it boils semi molten rocks in the mantle and slowly moves the crust above it
How do plates move?
They float on the semi-liquid mantle layer below and drift very slowly across the surface (as fast as your finger nails grow)
Name 4 types of plate boundaries
Constructive
Destructive
Conservative
Collision zones
Plate boundaries characteristics
Constructive - apart
Destructive - sinks
Conservative - slides
Collision zones - together
Where do earthquakes affect the world today?
The populated regions around the Pacific Ocean
How do volcanoes erupt?
Molten material from the mantle (magma) is forced though an opening or vent in the earth’s crust onto the surface as lava which solidified as igneous rock.
What are the two types of volcanoes?
1.Shield volcanoes
2.Stratovolcano volcanoes
Benefits of volcanic activity
1.Geothermal power heats homes, swimming pools and is used to melt snow
2.Tourists came to visit the geothermal wonders like geysers
3.Volcanic ash is a natural fertiliser
Problems of volcanic activity
They spew hot gases, ash, lava and rocks that are powerfully destructive.
They can also cause floods and power outages
What causes earthquakes?
Sudden movement of the earth’s tectonic plates
What are the short term causes of the Japan earthquake?
Death and injury - 15,894 people died and 6,152 were injured and 2,562 were missing
What were the long term impacts of the Japan earthquake?
Nuclear contamination of soils and sea water, and evacuation of a large number of residents in surrounding areas
How can earthquake hazards be reduced?
Governments organise earthquake drills and also are constructing new buildings
What caused the Indian Ocean 2004 Boxing Day earthquake?
By the subduction of the Australian plate beneath the Eurasian plates.
5 earth facts
1 globe
2 hemispheres
5 oceans
7 continents
8 billion people
What are lines of latitude?
They point in a east west direction and allow us say how far we are north or south
What are lines of longitude?
They run from north-south and allow us to sat where we are,east or west
What is the prime meridian?
It is the central line of longitude on the globe
Where do most volcanoes occur
Destructive and constructive plate boundaries
How many active volcanoes are there
About 500
3 examples of volcanoes
Mt St Helens(USA), mt Meripi (Indonesia) and mt. Ejya (Iceland)
What is pyroclastic flow?
White hot avalanche of exploded rocks
What is the epicentre
The point directly above the earthquake where the magnitude is the greatest
Where do earthquakes occur
At fault lines
What is the focus
The focus of an earthquake is the point below the surface at which the pressure is released
