S-Cool Revision Summary

S-Cool Revision Summary

  • The Earth's crust is made up of seven principal tectonic plates and numerous other smaller plates.
  • The plates move due to convection currents in the mantle.
  • There are two different types of plate: oceanic (dense, thin) and continental (light but thick)
  • Destructive plate boundaries cause violent volcanoes and earthquakes, as well as deep-ocean trenches and fold mountains.
  • Volcanoes and earthquakes do occur on constructive plate boundaries. They also cause mid-ocean ridges to form.
  • The main effects of a conservative plate boundary are earthquakes, which can be fairly violent and frequent.
  • At collision plate boundaries the two plates push into each other forcing material to be folded up into huge mountain ranges.
  • Volcanoes are formed along two types of plate boundary: destructive and constructive boundaries.
  • There are three main volcanic cones: acid lava cones, composite cones and basic lava cones.

Examples: Mt. St. Helens (USA) & Mt. Pinatubo (Phillipines)

  • Earthquakes occur along faults, caused by the sudden jerking movements of the fault, either laterally or vertically.
  • Earthquakes are measured in two ways; The Richter Scale and the Mercalli Scale
  • The point at which an earthquake actually begins, deep below the earth's surface is called the focus.
  • The point directly above the focus, on the earth's surface, is called the epicentre.
  • The effects of an earthquake are described as being primary or secondary.

Examples: Kobe (Japan); Izmit (Turkey).

  • Form along both destructive and collision plate boundaries, in other words where two plates are pushing towards each other.
  • The best examples are the Himalayas, the Rockies, the Andes and the Alps, all of which are huge fold mountain ranges caused by the collision of two plates.
  • Humans use Fold mountains for a wide variety of purposes, including farming, tourism, forestry industry and hydro-electric power production:
  • Natural hazards will affect More Economically Developed Countries (MEDC's) in a differing way to those which occur in Less Economically Developed Countries (LEDC's).