The structure of Earth

• During an earthquake , seismic waves travel outwards from the earthquake (The can travel all the way through the earth) - Seismic waves travel in a curved path through the earth, due to the earth increasing in density with depth - detectors placed around the Earth measure when and where the different waves arrive
• During an earthquake, what are detectors that are placed around the earth capable of doing?

  Measuring where and when the different waves arrive
• S waves cannot travel through the liquid outer core of the Earth - This results in a large shadow zone on the opposite side of the Earth to where the earthquake originated. -This shadow zone provides evidence of the size of the Earth's core
• P-waves are able to travel through the liquid outer core of the Earth - but are refracted between the semi solid mantle and liquid outer core - and are refracted again between the liquid outer core and solid inner core. -These refractions result in P-wave shadow zones - which when studied are used to determine the size and composition of the inner and outer core