GCSE Geography Unit 2 - Tectonic Landscapes

Tectonic Landscapes

What are plate tectonics? Plate tectonics is a theory that gives an explanation for the location of earthquakes and volcanoes. The Earth's crust is divided into these plates. These plates move a few centimetres every year as they are floating on the mantle. This movement is caused by convection currents in the mantle. This movement causes the plates to collide or move apart.

What are hotspots? A hotspot is another place where volcanoes can occur. Hotspots are fixed points in the mantle which generates heat and they usually occur under oceans. This intense heat causes a build up of pressure and magma rises through the crust. This causes volcanoes.

Divergent plate boundaries:This is where plates are moving apart from each other. As the plates move apart, a gap is left in the middle and magma will rise up from the mantle. If the magma reaches the surface a volcano will emerge.

Conservative plate boundaries: This is when plates are moving alongisde each other in the same direction at different speeds or in different directions. The plates become stuck at a pressure point and eventually the crust will snap and the plates will suddenly move. Earthquakes occur hear.

Convergent plate boundaries:

Two Continental Plates Meet: Two plates move in the same direction towards each other. No volcanoes are formed as the crust is not being melted or subducted. The crust rises to form mountains and earthquakes can occur here.

Continental and Oceanic Plates Meet: The oceanic plates goes beneath the continental plate because it is denser. The edge of the oceanic plate begins to melt and it forms magma. The magma forces its way upwards to form a volcano.

Methods to measure earthquakes:

Mercalli Scale: It is a measurement of the intensity of the earthquake conpleted by eyewitness accounts. It is measured on a scale of 1-12 and the person has to be present at the earthquake site.

Richter Scale: It is a measurement of the magnitude of the earthquake completed by a sesimograph. Measured on a scale of 1-9 where each number…