Mid-plate Tectonic Activity

Whilst most tectonic activity is focused on plate margins, it is possible for earthquakes and volcanoes to occur far from the edges of tectonic plates.

The causes of intraplate earthquakes are not fully understood. Some are associated with pre existing weaknesses in plates which can become reactivated. The series of earthquakes which took place in New Madrid, Missouri, in 1811-12 and the 2001 Gujarat, NW India earthquake are examples of intraplate earthquakes which caused significant destruction.

Intraplate volcanoes are thought to be associated with ‘hot spots’ in the mantle, which remain stationary as plates move over them. The mechanism by which such hot spots produce volcanic activity is a subject of much debate amongst Earth scientists. Some have suggested they are caused by mantle plumes – cylindrical bodies of material hotter than the surrounding mantle. The plumes are thought to originate at the outer core/lower mantle boundary, rising upwards to the base of the lithosphere over many millions of years.

Case study:

Hawaiian Islands