An earthquake is an intense shaking of Earth's surface. The shaking is caused by movements in Earth's outermost layer.
Tsunamis are usually associated with earthquakes however the risk for a tsunami along the Queensland coast is very low. The most likely impact for us is called a “marine threat”. This is when unusual waves, dangerous rips and currents that can put swimmers and mariners in danger.
Earthquakes often happen without warning. Severe quakes can result in property damage, injury, and loss of life. They can cause fires, tsunamis, landslides and avalanches, and volcanic eruptions.
The size of an earthquake is known as its magnitude. The higher the number, the more powerful the earthquake.
What are the local risks?
In August 2015, a magnitude 5.7 earthquake occured approximately 120km offshore from K'gari (Fraser Island). This was followed a little over an hour later by a magnitude 5.1 earthquake, again approximately 120km to the east of K'gari. Earthquakes represent a rare but ever-present risk to all communities across Queensland.
Earthquakes in QLD occur because the Australian plate is moving northward at approximately seven centimetres per year, colliding with the Pacific plate, causing stress to build up across Australia, which is released periodically by earthquakes.
The impact of earthquakes is dependent on their scale as outlined below.
Intensity and impacts
2.5 or less
Usually not felt, but can be recorded by seismograph
2.6 to 5.4
Often felt, but only causes minor damage
5.5 to 6.0
Slight damage to buildings and other structures
6.1 to 6.9
May cause a lot of damage in very populated areas
7.0 to 7.9
Major earthquake, serious damage
8.0 or greater
Great earthquake, can destroy communities near the epicentre
How can I prepare for the impacts of an earthquake?