Structure of the Earth

earth is made of a layered structure & has;
1. thin, rocky crust
  1. mantle
    1. core (containing iron)
difficult to collect info about structure of earth
deepest mines and holes drilled into the crust are only a few KM into the crust
scientists have to rely on studying seismic waves (vibrations) caused by earthquakes to understand the structure of the Earth
Earths lithosphere is cold, rigid outer part of earth made of crust & top part of mantle
top of lithosphere is cracked into 7 parts interlocking called Tectonic Plates
1. oceanic plates sit under the ocean
  1. continental plates for continents
plates sit on top of mantle as they are less dense than the mantle
1. plates move about 2.5cm each year
  1. this causes earthquakes & volcanoes at the boundaries between plates
many theories have been put forward to explain changes in the earths surface
1. earth scientists accept the theory of plate tectonics
  1. this theory is widely accepted as it explains a range of evidence
    1. it has been used and tested by many scientists

Resumo de Recurso

	Criado por alicekilcullen mais de 11 anos atrás