Plate Tectonic Facts



  • The Earth’s surface is divided into slabs called tectonic plates. Each plate is a fragment of the Earth’s rigid outer layer, or lithosphere.
  • There are 16 large plates and several smaller ones. Plates are approximately 100 km thick but can vary in thickness from 8 km to 200 km.
  • The biggest plate is the Pacific plate, which underlies the whole of the Pacific Ocean. The Pacific Ocean represents half of the world’s ocean area.
  • Tectonic plates are moving all the time – by about 10 cm a year. Over hundreds of millions of years they move vast distances. Some have moved halfway round the globe.
  • The continents are embedded in the tops of the plates, so as the plates move the continents move with them.
  • The Pacific plate is the only large plate with no part of a continent situated on it. It represents more than one-third of the Earth’s surface area.
  • The movement of tectonic plates accounts for many things, including the pattern of volcanic and earthquake activity around the world.
  • There are three kinds of boundary between plates: convergent, divergent and transform.
  • Tectonic plates are probably driven by convection currents of molten rock that circulate within the Earth’s mantle.
  • The lithosphere was too thin for tectonic plates until 500 million years ago.