Tectonic Plates Flashcards
Crust
The crust is a solid layer of rock on the surface of the planet. The thickness varies between 3-30miles
Mantle
The mantle is a semi-liquid layer of magma or molten rock that moves due to convection currents
Outer core
The liquid part of the core which has a similar composition to the inner core
Inner core
The inner core is the solid part at the centre of the earth. It is made of iron and nickel and has temperatures reaching 5500 degrees
Pink animals eat an important cake noon, soon and in January. in autumn pink nuts can speak
Pacific
African
Eurasian
Arabian
Indo-Australian
Caribbean
North American
South America
Juan de fuca
Antarctic
Philippine
Nazca
Cocos
Scotia
Describe the crust
It 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
What causes the crust to move
The heat from the inner core tried to escape and “boils” semi-molten rocks in the mantle which slowly moves the crust above it
What are the movements of the plates by the mantle called
Convection currents
Arrows down
Plate converge/ destructive plate boundary
Arrows up
Plates diverge constructive plate boundary
Constructive plate boundaries
Example =North America plate and Eurasian plate with mid Atlantic ridge down the middle
Find=volcanoes
Forms volcanic islands (eg Iceland islands)
Pulling away of plates forces magma up that cools to form new islands
Destructive plate boundary
Example=nazca and South America plate
Plates move towards each other and cause volcanoes and earthquakes
The denser oceanic plate will subduct to the continental plate causing a subduction zone and oceanic trench to form
Collision plate
Example =Eurasian plate and Indo-Australian plate
Two continental plates move towards each other and force each other upwards to form fold mountains(e.g. Himalayas)
Earthquakes occur
Conservative plate boundary
Example=North America plate and pacific plates San Andreas fault
Earthquakes
Plates move past each other
What is volcano
A volcano is an opening or rupture in the Earth surface or crust which allows hot magma volcanic ash and gases to escape from below the surface
Main vent
The opening for the magma to go up through the volcano
Magma chamber
The source of the Milton rock
Crater
The circular basin shape on the top of the volcano
Secondary cone
A secondary vent formed in the side of the mountains
Volcanic bombs
Airborne material from a volcanic eruption
Active
A volcano that could erupt at any point
Dormant
A volcano that is ‘spleeping’ and has not erupted for years
Extinct
A volcano that is unlikely to erupt ever again
What are some hazards of volcanoes
Ash
Gas
Acid rain
Lahar
Pyroclastic flow
Lava flow
Hazards of ash
The smoke cloud normally seen from an eruption is ash
This travels for miles and settles as ashfall
This can produce very fertile soil
Hazards of gas
Volcanoes produce gas when they are erupting
This includes carbon dioxide steam and sulphur dioxide
Volcanic gases smell of rotten eggs due to the sulphur that is present
Hazards of acid rain
The sulphur emissions from volcanoes can cause acid rain
Acid rain can be dangerous to plant and animal life
It can also harm humans
Hazards of a Lahar
Lahar is a mudflow that comes from a volcano
It can be dangerous due to its energy and speed
It is fluid when moving but solidifies when stopped
Hazards of pyroclastic flow
Pyroclastic flow are floods of gas, lava and rock that rush down the volcano after an interruption
Their hot gases and high speeds make them lethal to anything in their path
Hazards of lava flow
Lava flow is created by a non-explosive eruption
It consist of molten rock
It is thick and can travel very far before solidifying
It can be very destructive, but it is slow. Moving
What are the benefits of lava and ash
Produces fertile soil once it has been weathered
What is the environmental benefit from lava
Geothermal energy means that the cost of living can be massively reduced (renewable energy)
What is the financial benefit of volcanoes
Volcanoes can help to generate income to the region through tourist numbers
How do volcanoes upheld wildlife species
volcanoes create new land overtime and provide habitats for several unique wildlife species
What are the 10 most active volcanoes
Kilauea-Hawaii
Mount Etna-Sicily
Stromboli-aedian
Mount Merapi-Indonesia
Piton de la Fournaise-réunion island
Eyjafjallajokull-Iceland
Mount yasur-Vanuatu
Sakurajima-Japan
Popocatépal- Mexico
Fuego-Guatemala
How does a spectrometers help predict an eruption
Volcanic emissions may increase before an eruption. spectrometers can be used to measure the amount of sulphur dioxide gas that is being admitted by a volcano
How does a seismometer help predict eruptions
Before an eruption magma collects in the magma chamber. The movement of magma can cause earthquakes. These can be measured using a seismometer
How can tiltmeters and geodimeters help predict an eruption
The shape of a volcano may change in the build up to an eruption due to magma gathering in the magma chamber and vents. Tiltmeters and geodimeters can measure any changes in the slope of a volcano
How does a thermometer predict an eruption
Water temperatures can rise before an eruption. A thermometer can be used to measure this. Water levels may also change if magma oozes onto the floor of a river or lake on the volcano
What is an earthquake
Earthquakes are vibrations of the earths crust caused by movement at plate boundaries of major fault lines
Where do most earthquakes occur
Earthquakes can occur at all four major plate boundaries but the most severe earthquakes usually occur a conservative and destructive plate boundaries
What do earthquakes produce
An earthquake produces long shockwaves(seismic waves) that travel out from the centre of the crust just like a stone being thrown in a pond
Describe the focus
The focus is the point where the earthquakes starts. The waves spread out from the focus. Near the focus waves are stronger, causing more damage
What Is the epicentre
The point on the Earth surface immediately above the focus
What causes an earthquake
When tectonic plates have been pushing against each other and the stored energy that has built up is released in shockwaves which cause the earth surface to shake
Why is it more dangerous for an earthquake to occur in a city than the country side
Not many people live in the countryside but in a city it’s very high built urban area that has loads of people in it loads of buildings that can fall because buildings not earthquakes kill people so it’s just a lot more dangerous
What is the Richter scale
The Richter scale can be used to measure the magnitude(power) of a tremor using an instrument called a seismograph
What type of scale is the Richter scale and what does this mean
It is a logarithmic scale. Which means a size 6 earthquake on the richer scale is 10 times larger than a size 5 and 100 times larger than a size 4. It cause up in x10 strength
What happens during an earthquake of 1-3
Not much, you wouldn’t really really notice this slight shaking for sensitive people
4-5
Can be felt by everyone doesn’t cause much damage windows they break poor constructed buildings may fall
6-8
Damage buildings, absolute catastrophe, collapse of Everything
9-10
Complete destruction shaking can could be felt from far away only occur once every three centuries
What are the short term impacts of an earthquake
Roads destroyed
Buildings collapse
Debris causes injury /death
Water or gas mains burst
Electricity cut off
What are some long term impacts of a earthquake
Disease
Mental trouble
People lose livelihoods
Tsunamis
Landslides
How do you plan to limit the impact of an earthquake
Emergency services can practice for disaster
Stockpile medicine foods blanket etc
Educate the population and what to do during and after an earthquake
How do you protect cities from an earthquake
Construct buildings and roads that stand shaking
How can we predict earthquakes?
Predicting earthquakes accurately enough to evacuate people is nearly impossible but:
Water levels can change in wells and lakes
Foreshocks can be detected by a size monometer and a tilt meter can detect movement within rock
Animals can act strangely before an earthquake
What factors can affect the level of damage done by an earthquake
Magnitude of the earthquake
Physical landscape
Time of day
Building design and construction
Emergency services response
GDP (gross domestic produce)
Education
How can buildings be adapted for an earthquake?
Rolling weights on the roof to counteract the shockwaves
Identification number on the roof visible to helicopters
Open areas for pedestrians to assemble
Automatic shutters come down over the windows
Deep and firm building foundations
Rubber shock absorbers beneath the buildings
What are tsunamis
Tsunamis are tidal waves caused by underwater earthquakes. A tsunami travels at speeds between 400 and 600 mph.
What was the cause of the case study of tsunami
On the 26th of December 2004 and nine earthquake occurred beneath the Indian ocean at the sundra trench(destructive plate boundary). the quake was caused by a slip along a fault in the earths crust where the Indian Australian is subducted below the Burma plate
What was the result of the case study tsunami
The crust ruptured at over 7600 km an hour along 1500 km section of fault
releasing more energy than 23,000 atomic bombs.
tsunami spread across the Indian ocean affecting coastal areas of 14 countries including Indonesia, SriLanka, India, Bangladesh, Myanmar, the Maldives and Malaysia.
over 226,000 people are presumed to have died in the disaster.
How, can we reduce the impact of tsunamis?
Offshore breakwater
trees on the beach to break up the waves
flood proof buildings for buildings within the inland limit of a one in a hundred year tsunami
Evacuation Road
normal safe development much further away from shore
What is the continental crust made of
Granite
Oceanic trench
A deep valley found in the ocean
Convection current
A circulating current of warmer material(such as magma)
Lithosphere
The crust and upper mantle form this
Ring of fire
Around the edges of the Pacific Ocean
Main type of rock in the oceanic crust
Basalt
The innermost layer of true earth
Core
