Hot Spots

• Plumes of magma assocated with plate movement. Plau,es of magma wear away at the centre of the plate.
• Areas of intense volcanic activity away from the plate margins / concentrations of radioactive elements inside mantle cause hot spot to develop.
• Form plume volcanoes, e.g. Hawaiian Islands, Emperor seamount chan.

1- caused by plume magma (vertical column of magma that rises up from mantle)

2- volcano forms under plate

3- magma plume remains stationary and the crust moves.

4- Plate moves- volcanic activity in area decreases.

5- New volcanoes form above the hot spot

6- chain of volcano forms- the magma plume doesn't move but the crust does, so as the crust moves the plume of magma eats away at different area of plate.

• Hot spot remains in the same place and the plate moves = line of volcanoes.
• Those above hot spot are active, those that are not above the plume are domrant- leaves a chain of extinct volcanoes (evidence of sea-floor spreading).
• Oldest volcanoes put pressure on the crust causing subsidence (sinking into crust again). Subsidence and marine erosion = reduced old volcanoes to Sea mounts.