What caused North QLDS’s earthquake?

We caught up with Geoscience Australia to chat about the magnitude 5.2 earthquake earlier this week, which was centred near the town of Eidsvold in northern Queensland.

Australia is generally geologically stable and, unlike New Zealand, not on fault lines or near where tectonic plates meet, so what causes the country’s earthquakes? This was Geoscience Australia’s response.

“Other than aftershocks of large earthquakes (e.g. the M6.6 in Tennant Creek in 1988), earthquakes in Australia are caused by the compression of the Australian plate which is drifting north at approximately seven centimetres a year.

“This movement causes strain to continental Australia and the  build-up of energy is released as earthquakes. These are called intraplate earthquakes.

“While the exact location and timing of earthquakes are not possible to predict, our seismic history does provide us with an indication of which areas are more prone to above average seismic activity.

“For example, the earthquake near Eidsvold in Queensland was located in an area known to have the highest earthquake hazard in Queensland.
“We have deployed aftershock monitoring equipment to the region and expect to acquire new data that will enable us to better understand this earthquake.”

And while, as we reported last year, mining and fracking have been identified with earthquakes in some instances (see Man-made earthquakes cause seismic rumblings), the agency ruled that out in this case:

This area has a long history of earthquakes of this size dating back to a magnitude 5.9 in 1883, and as recent as a magnitude 4.4 in 2004.
Today’s earthquake was located 40km NE of Eidsvold and 80km east of Bundaberg in a remote area well away from any large mines or fracking activity. Based on the location and strong history of seismic activity in the exact area it is difficult to draw any link between mining activities and this earthquake.

More information on Australia’s earthquake hazard map can be found on the Geoscience Australia website.

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