Australia has a new biggest earthquake

By Jared Richards 12 May 2016
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The records have been given a shake up: a 6.6 magnitude earthquake in Tennant Creek, NT, in 1988 is now officially our biggest on record.

OUR HISTORY BOOKS need reprinting: Geoscience Australia has released revised magnitude scores of Australia’s earthquakes and with them, a new title holder for the country’s biggest earthquake.

Australia’s largest recorded earthquake now occurred on 22 January 1988 at Tennant Creek, an outback town in the Northern Territory. Three consecutive earthquakes occurred: the largest had a magnitude of 6.6.

Remarkably, despite its size, no injuries were reported due to the earthquake, although damage costs equalled $2.5 million, and thousands of aftershocks continued throughout the Territory for several years.

Comparing this to the 1989 Newcastle earthquake, which at magnitude 5.6 killed 13 people, hospitalised 160, and caused $4 billion of damage, Australia’s new record-holder didn’t leave the impact that its new title implies.

RELATED: Australia’s worst earthquakes

By revising the ways in which magnitudes are recorded, Geoscience Australia has downsized the previous record holder, the Meeberrie, WA earthquake of 1941, from a magnitude 7.2 to 6.3. The previous number was based predominantly off personal reports, including the diary records of a local homestead owner, lacking more detailed or precise recording data.

But by comparing these accounts to an international database and our deeper understanding of Australia’s seismicity, the International Seismological Centre has reigned in the hyperbole for a more accurate measurement.

Many older earthquakes are considered to have exaggerated magnitudes: as both scientists and the public were less educated on seismic shifts and there were fewer recording stations, it’s hard to separate these records from the shocks and traumas of personal experience. The centre’s revision is part of a worldwide attempt by seismologists to re-shift magnitude scores to establish the levelled facts.

In doing so, seismologists can create more accurate earthquake hazard maps, allowing them to estimate future shifts and push for pre-emptive protective measures.

With the revisions, the list of Australia’s largest magnitude earthquakes has been reshuffled. The list has a few qualifications: it’s restricted to earthquakes that occured on mainland Australia after 1900, as previous dates were not reviewed. 

Australia’s largest earthquakes by magnitude

  1. 6.6 Tennant Creek, NT – 1988 (revised from 6.7)
  2. 6.5 Meckering, WA – 1968 (revised from 6.9)
  3. 6.4 Simpson Desert, NT – 1941 (revised from 5.6)
  4. 6.3 Tennant Creek, NT – 1988 (revised from 6.4)
  5. 6.3 Meeberrie, WA – 1941 (revised from 7.2)
  6. 6.2 Collier Bay, WA – 1997 (revised from 6.4)
  7. 6.2 Tennant Creek, NT – 1988 (revised from 6.3)
  8. 6.1 Cadoux, WA – 1979 (revised from 6.2)
  9. 6.0 West of Lake Mackay, WA – 1970 (revised from 6.0)
  10. 6.0 Warooka, SA – 1902 (revised from 6.0)