Earthquakes are vibrations in the ground caused by energy being rapidly released from rocks. Unlike most earthquakes, ones occuring in Adelaide do not occur at a plate boundary. Rather, they are intraplate earthquakes. These earthquakes occur as a result of pressure being exerted on a tectonic plate from collisions between plates moving in different directions, and having its pressure being relieved at weak points in the plate’s interior which are usually at fault lines. Faults offer less resistance to pressure as they are planar fractures in rock. Intraplate earthquakes are much rarer than interplate earthquakes. The Earthquakes in the Adelaide regions are occuring because the Australian tectonic plate is being compressed by the movement of the Eurasian, Philippine and Pacific plates. The pressure accumulated is being released in Adelaide earthquakes mainly because of the faults in the region including the Edens-Burnside fault line which the 1954 Adelaide earthquake was attributed to.
Potential future earthquakes in Adelaide pose a potential hazard of property damage, injury and loss of life based on the long history of such occurences in the Adelaide region and the relation of the region to the Australian and surrounding tectonic plates. Earthquakes pose the risk of falling buildings and parts of building such as unsecured awnings, large signs and flying glass from broken windows; and risk of fire from broken gas lines and power lines. Earthquakes in the nearby ocean pose a tsunami risk similar to the 2011 Fukushima earthquake in Japan. People may also be harmed by being thrown by ground shaking. This is particularly dangerous inside of buildings where people can collide with objects and the inside of structures. Earthquakes could also possibly cause transport accidents and cause heart attacks among people with elevated risk.
Earthquakes in Adelaide 