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​Image of Kalgoorlie earthquake damage (April 2010) 

​​​​Earthquake​​

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​What is an earthquake? 

An earthquake is the sudden​ release of stress built up within the earth's crust. When the crust fails, energy waves are released which people and structures nearby experience as shaking. 

 

​​​What are aftershocks? 

​​Aftershocks are smaller earthquakes triggered by the initial shock. Aftershocks generally decrease in number and intensity over time. 

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Where do earthquakes occur? 

Most ea​rthquakes occur along plate boundaries. However, areas within plates, such as Australia, do experience occasional large intraplate earthquakes. WA has a long history of this type of event.​​

H​ow are earthquakes measured? 

There ar​e t​wo different ways to measure earthquakes:
 
  • Richter scale: measures the relative energy rele​​​ase during an earthquake.
  • Modified Mercalli Index: is a measure of what people feel during an ​​earthquake, how much ground shaking there was and how much damage there was.

 

How often do earthquakes occur?

Earthquakes of magnitude 4 or less are reasonably common in Western Australia. Roughly one magnitude 4 earthquake occurs every five years in the Meckering area (~130 km east of Perth). The most active earthquake area in Australia is Burakin (~250 km north-east of Perth) where a magnitude 5.0 earthquake in September 2001 was followed by ~18,000 aftershocks over the following six months.

Can we predict earthquakes? 

Scientists have never predicted a major earthquake. They don’t know how to and don’t expect to in the near future. However probabilities can be estimated for potential future earthquakes, looking at the likelihood that an earthquake will strike a particular area.

 

​What are the impacts of an earthquake? 

Possible impacts of an earthquake include:

  • Damage to buildings and infrastructure from shaking
  • Fire is common after an earthquake, especially when gas or downed power lines are present
  • Rock fall, landslides and toppling of masonry can be trigged by an earthquake greater than magnitude 4
  • Tsunamis are possible in the event of large off-shore earthquakes (magnitude >8)
  • Injury and death resulting from the above

 

Why can one earthquake cause more damage than another?

​​The damage caused by an earthquake is dependent upon both the magnitude of an earthquake and the distance from the earthquake focus to vulnerable elements (e.g. buildings, people). Consequently, a smaller magnitude earthquake that is close to vulnerable elements can potentially cause more damage than a larger magnitude earthquake that is further away from vulnerable elements.

 

Are we at risk​?

The nature of intraplate earthquakes make predicting risk difficult. However the history of earthquakes in the state demonstrates there is potential for large earthquakes.

MECKERING 1968 EARTHQUAKE

On 14 October 1968, a magnitude 6.9 earthquake struck the town of Meckering.

The town was destroyed and twenty people were injured but there were no deaths.

The earthquake caused ground movement which broke railway lines  and ruptured major roads to Meckering.

Considerable shaking occurred in Perth alarming residents  and causing damage to many older buildings.

 

Full Factsheet dow​​nload:​


Earthquake factsheet​ (593KB)


 

 

Watch our Earthquake Hazard educational video​ (8.25​​​​​​ min):


 


Further information about this hazard​​

More information ​about Earthquake can be found at: