One month after the largest earthquake to hit south-eastern Australia in more than 200 years, small aftershocks are still being recorded by Geoscience Australia’s National Earthquake Alerts Centre.
The 5.9 magnitude earthquake, north of Rawson in Victoria on 22 September, was felt across six states and territories – including in the major centres of Melbourne, Hobart, Adelaide, Canberra and even Brisbane.
Resources minister, Keith Pitt, said the quake has demonstrated the valuable role the Australian Government’s world-renowned National Earthquake Alerts Centre plays in detecting and preparing for disasters.
“Seismic analysts were able to provide Emergency Management Australia’s National Situation Room with preliminary details about the size, location and depth of the quake approximately 10 minutes after this earthquake occurred,” the minister said.
Information helps to mobilise the response
“This information helped local emergency managers gauge the severity of the quake and start mobilising their response.”
The Alerts Centre has detected approximately 30 aftershocks in the month following the quake, ranging in magnitude from 2.2 to 4.1, including one last night.
Geoscience Australia’s Earthquakes@GA website also received more than 40,000 felt reports in the first 24 hours – a new record for an Australian earthquake.
These reports, made by members of the public, are used to produce a calibrated ShakeMap showing the modelled ground-motion intensity over a broader area.
“The National Earthquake Alerts Centre is continuing to receive felt reports from the community and will continue to assess the shaking intensity of each report,” Pitt said.
“This ‘citizen science’ will feed into Geoscience Australia’s seismic hazard modelling work, which will help keep Australians safer in future.”
Permanent network of more than 100 stations
The National Earthquake Alerts Centre uses a permanent network of more than 100 stations across the country to detect and respond to earthquakes 24 hours a day, 365 days per year.
On average, it detects and locates approximately 100 earthquakes of magnitude 3.0 or larger per year.
Australia experiences an earthquake around the size of the one that occurred in Victoria on average every five to 10 years. However, most large earthquakes tend to occur in remote central and western Australia.
“This event reminds us that large earthquakes can occur anywhere across Australia without warning,” Pitt said. “No technology can predict earthquakes, but we can certainly prepare for them.”