Plate Tectonics Flashcards
What is the mantle
The mantle is a semi liquid layer of magma that moves due to convection currents
What is the crust
The crust is a solid layer of rock on the surface of the planet. The thickness varies between 3 and 30
What is the outer core
The liquid part of the core which has a similar composition to the inner core
What is the inner core.
The inner core the solid part at the centre of the earth it’s made of iron and nickel and has temperatures reaching 5500c
How do convection currents cause the tectonic plates to move
The crost is broken up into seven large sections and various smaller sections which are floating on the mantle and moving towards, away from and past each other. The heat from the inner core tries to escape and (boils) semi-molten rocks in the mantle and slowly moves the crust above it
What plate boundary is the indo Australian plate
Collision
What type of plate boundary is the South American plate
Deconstructive
What type of plate boundary is the North American plate
Constructive
What type of plate boundary is the Eurasian plate
Conservative
What is a volcano
A volcano is an opening or rupture in the earths surface of crust which allows hot magma, volcanic ash and gases to escape from the surface
What is a main vent
The opening for the magma to go up through the volcano
What is the magma chamber
The source of the molten rock
What is the crater
The circular basin shape on the top of the volcano
What is the secondary cone
A secondary vent formed on the side of the mountain
What are volcanic bombs
Airborne material from a volcanic eruption
What does active mean
A volcano that could erupt at any given point
What does dormant mean
A volcano that is sleeping and hasn’t erupted for years
What does extinct mean
A volcano that will never be active again
Volcanic hazards
Ash
The smoke cloud normally seen from an eruption is ash.
It can travel several miles and settles as ash-fall
it can produce very fertile soil
Volcanic hazards
Gas
Volcano produce gas when they are erupting.
This includes co2 steam and sulphur dioxide volcano gases smell of rotten eggs due to the sulphur present.
Volcanic hazards
Acid rain
The sulphur emissions from volcanoes can cause acid rain
Acid rain can be dangerous to plant and animals it can also harm humans
Volcanic hazards
Lahar
Lahar is a mudflow that comes from a volcano.
It can be dangerous due to its energy @nd speed. It’s fluid when moving solidifies when stopped
Volcanic hazards
Pyroclastic flow
Pyrclastic flows are floods of gas lava and rock that rush down the volcano after an eruption. Their hot gases and high speed make them lethal to anything in their path
Volcanic hazards
Lava flow
Lava flow is created by a non-explosive eruption.
It consists of molten rock
It’s thick and can travel very far before solidifying
It can be very destructive but it’s slow moving
What are benefits of volcanoes
Lava produces fertile soil once its been weathered
Geo-thermal energy means that the cost of living can be massively reduced
Volcanoes can help to generate income to the region through tourist numbers
Volcanoes create new land over time and provide habitat for several unique wildlife species
How can you predict volcanoes
Volcanic emissions may increase before an eruption
Spectrometers can be used to measure the amount of sulphur dioxide gas that is being produced but the volcano
Before an eruption magma collects in the magma chamber the movement of magma can cause earthquakes these can be measured by using seismometer
The shape of a volcano may change in the build up to an eruption due to magma gathering in the magma chamber or vents. Tilt-meters and geometers can measure any changes in the slope of a volcano
Water levels may also change if magma Oozes onto the floor of a river or lake on the volcano which is measured by a thermometer
What are earthquakes
Earthquakes are vibrations of the earths crust caused by movement at plate boundaries and major fault lines. Earthquakes can occur at all major plate boundaries but the most severe earthquakes usually occur at conservative and destructive plate boundaries
What causes an earthquake
An earth quake is when the ground shakes. It produces long shocks that travel out from the centre of the crust just like a stone being thrown into a pond. The waves spread out from the focus. The focus is the point where the earthquake starts. Near the focus the waves are stronger causing more damage. The epicentre is the point on the earths surface immediately above the focus
How is a earthquake measured
The Richter scale can be used to measure the magnitude of a tremor using an instrument called a seismograph. It’s a logarithmic scale which means that a size 6 earthquake on the scale is ten times larger than a size 5 and 100 times larger than a size 4
Impacts of earthquakes
Short term
Roads destroyed
Buildings collapse
Debris cause injury/death
Water or gas mains burst
Electricity cuts off
Impacts of earthquakes long term
Disease
Mental trauma
People lose livelihood
Tsunamis
Landslides
How can you limit earthquake damage
Emergency services can practice for disaster
Stock up on medicine food blankets
Educate the population in what to do during and after
Construct buildings and roads that withstand shaking
What are tsunamis
Tsunamis are tidal waves caused by underwater earthquakes. Tsunami means harbour wave in Japanese. Tsunamis travel at speeds between 400 and 600mph
The Indian Ocean earthquake
On 26th December 2004 a magnitude 9 earthquake occurred beneath the Indian Ocean at the sundra trench. The earthquake caused by a slip along a fault in the earths crust where the indo-Australian plate is subdued by the Burma plate. The tsunami spread across the Indian Ocean affecting coastal areas of 14 countries
