Term 3 Flashcards
What are features of the oceanic crust, (what is it made of? How thick? density?)
- Basalt
- 5-10km thick
- More dense than the continental crust
The oceanic crust is still being formed, around 17km3 of oceanic crust is made from molten lava every year.
What are features of the Continental crust? (what is it made of? How thick? density?)
- Granite and other plutonic rock
- 30-50km thick
- Less dense
What is the mantle made of?
Silicate rock, it is rich in iron and magniseum
What is the lithosphere and its features?
- makes up the tectonic plates
- Rigid
- Break easily
- Uppermost mantle and crust
What is the aesthenosphere and its features?
- top part of the mantle
- Below lithosphere
- Flowy and plastic like
What is the mesosphere and its features?
- bottom part of the mantle
- Strong and rigid rock
what are features of the outer core?
- Liquid
- Motion within it generates earth’s magnetic field
What are features of the inner core?
- Solid due to the pressure
- Iron and nickel
- Extremely hot
What is pangea?
The name of the continents before they drifted apart
What is a Mesosaurus?
A fresh water animal with fossils found in the southern tip of South America and Africa
What is sea floor spreading?
Sea floor spreading is when magma breaks the crust and rises, pushing the crust out of its way and creating new sea floor.
Define Longitude
How far east or west of the prime meridian something is
Define latitude
How far north or south of the equator something is
what are transform plate boundaries? and what can this form?
When the tectonic plates slide past each other.
- They are not smooth so there is lots of friction and pressure
- If they get caught the pressure builds up, when the plate suddenly moves it creates earthquakes
What are Converging plate boundaries?
When two continental plates push into each other
What happens at a converging boundary (oceanic and oceanic)?
The denser oceanic plates is forced under the less dense plate.
- Creates oceanic trenches, underwater volcanoes
- Subduction zone
What happens at a converging boundary (oceanic and continental)?
- The oceanic plate is forced underneath the continental plate
- Lithosphere is forced into the mantle
- Creates trenches and volcanoes
What happens at a converging boundary (continental and continental)?
The two continental plates of equal densities fold up from each other. This creates mountain ranges.
What are diverging plate boundaries?
When two tectonic plates pull away from each other
What happens at a diverging plate boundary (continental and continental)?
- Sometimes fill up and create new oceans, this is how the Atlantic ocean formed
- Creates valleys
What happens at a diverging plate boundary (oceanic and oceanic)?
- Sea floor spreading
- Magma pushes through the sea floor creating sea ridges, then cools and creates new sea floor
- Creates rifts and ridges
What is an earthquake?
The shake that is caused by the release of energy after two tectonic plates get stuck.
What is the focus/hypocentre?
The position where the strain energy stored in the rock is first released.
What is the epicentre of an earthquake?
The closest point on land directly above the fault
What are P waves?
- Primary waves
- The first body waves of the earthquake
- Originating from the focus of the earthquake
What are S waves?
- Secondary waves
- The second body waves of the earthquake
- Originating from the focus
What is a seismogram?
The instrument that records the waves of an earthquake
What is a tsunami?
- Big waves
- Caused by earthquakes under the water
- The more dense plate slide under the other, these can get stuck, the pressure is released when it’s too much. One plate is thrust upward while the other is pushed down. The water is also thrust upwards which creates a big wave, also known as a tsunami.
define retrofitting?
the addition of new technology to older buildings
What is cross bracing?
two diagonal supports placed in an X shape manner
