The earths straucture Flashcards
Describe what makes the tectonic plates move. (Include a description o why/how convection currents in the mantle come from.)
Convection currents in the Mantle move the tectonic plates. Convection currents form as the base of the mantle is heated by the outer core and therefore becomes less dense and rises replacing the mantle near the crust that has cooled making it more dense and sink. Thus creating a circular motion in the Mantle that moves the tectonics plates.
List the four layers of the earth and describe them.
Inner core- solid, it is very hot, it is made up of iron, both p-waves and s-waves can travel through but s-waves can’t get to it due to the ayer of liquid surrounding it. Very dense
Outer core- liquid, less dense than the mantle, p-waves can travel through it but s-waves are unable, it is hot, the density increases towards the centre there for the p-waves refract.
Mantle- solid-ish, s+p-waves can travel through, this is the largest layer, warm, denser than the outer core but not as dense as the inner core.
Crust- thick, made up of tectonic plates, solid
rock, both p+s-waves can travel through it
What causes earthquakes?
Earthquakes happen when tectonic plates suddenly move against each other. this occurs when convection currents push/pull tectonic plates against each other so pressure builds up. When the pressure gets too much the tectonic plates will suddenly slip past each other therefore causing an earthquake.
What causes and what is an under water tsunami?
It is an underwater earthquake.
What kind of damage can earthquakes and tsunamis cause?
Seismic waves are released and can cause serious damage to structures and if it is a tsunami flooding could cause serious damage.
What information could scientists use to predict the likelihood of an earthquake?
Scientist can only look at previous earthquakes and the length of time since the previous earthquake. This is useful as they ma not be able to predict the exact time an earthquake will occur but it is useful as they can get a rough estimate.
