What caused the recent earthquakes in Australia? How can
earthquakes happen in places like Australia that are far from
the edges of tectonic plates? How can earthquakes happen in
places like Australia that are far from the edges of tectonic
plates? Why are some parts of the world more active than others?
Earlier this year, a 5.7 earthquake hit the north of South
Australia, far from the edges of the Indo-Australian plate on
which Australia sits. While most earthquakes occur along
tectonic plate boundaries, a small number occur along faults in
the normally stable interior of plates. These quakes are known
as intraplate earthquakes. The SA quake reactivated a well-known
fault system in the Musgrave Ranges of northern South Australia,
says petrologist Professor Bill Collins from the University of
Newcastle. "Consider the earth like an egg. It has a shell and a
soft interior. The shell is composed of rigid plates, tectonic
plates, and in some places they move towards each other and in
others they draw away from ea