An earthquake that shook buildings across much of south-eastern Australia on Wednesday was the biggest onshore tremor in Victoria’s recorded history – and is likely to set off months of aftershocks.
A watch-and-act level alert was issued for all of Victoria following the initial 5.8 magnitude earthquake.
There have been aftershocks every few minutes since the 9.15am tremor near Mansfield in the state’s north-east, the largest a 4.7 quake just 18 minutes after the first.
Seismology Research Centre chief scientist Adam Pasquale said the magnitude 4.7 quake was significant.
“That in itself would’ve been a pretty exciting day but it was overshadowed by the 5.8,” Mr Pasquale said.
Aftershocks are common following tremors and Mr Pascale expects them to go on for months. So far, they have largely ranged between a magnitude 2.0 and 3.0.
- Related: Rare earthquake strikes Victoria
Victoria’s Deputy Premier James Merlino said he had spoken to Emergency Management Commissioner Andrew Crisp about the disaster and urged residents to observe emergency warnings.
“Geoscience have confirmed there is a possibility that we may receive further aftershocks and potential risk of further earthquakes. Indeed, more aftershocks could occur for weeks, if not months,” he said.
He said buildings had been damaged at the epicentre in Mansfield, as well as in the Melbourne suburbs of Kensington, Ascot Vale, Prahran, Balwyn, Northcote and West Melbourne.
Incident control centres were set up at Mansfield, Dandenong and Benalla and helicopters were sent out but no injuries have been reported, he said.
Power has mostly been restored after about 35,000 customers reported outages across the state, including at Beechworth Hospital.
“We’re talking aftershocks that people may not feel ever, but earthquakes of this magnitude we’ve had before go on for years,” Mr Pasquale said.
Seismological instruments were still recording aftershocks from a magnitude 5.2 earthquake near Baw Baw in 1996, he said.
It is also possible that Wednesday’s shake might be a foreshock for a larger earthquake.
The initial Baw Baw earthquake in 1996 was a magnitude 3.5 that was followed 90 minutes later by a magnitude 5.0, while a 4.7 magnitude quake in 2009 was followed with another of the same size two weeks later.
“It’s always possible that this is not the largest event of the sequence,” he said.
“But it’s unlikely. What we’ve seen in the past when we’ve had events of this sort of magnitude is they usually tail off with smaller aftershocks.”
Videos have emerged on social media from the snowfields at Mount Buller, about 50 kilometres from Mansfield, with skiers caught on snowcams making their way down a very shaky slope.
Mr Pascale said he had heard reports of tremors being felt about 1000 kilometres away in Newcastle, which was devastated by a magnitude 5.6 earthquake in 1989.
“Our part of the world is a stable continental region – it’s old, hard rock and energy travels really far in hard rock,” he said.
Photos and videos of a damaged Betty’s Burgers building in Windsor, in inner-Melbourne, flooded the internet, with the ABC speaking to the restaurant’s owner, Rodney.
“We have had some damage, but the main thing is everybody is safe,” he said.
He said only one person was in the building when the quake hit, and they got out safely.
“Just a bit of a surprise, earthquake in Windsor! Hard to believe.”
Rodney said he was at home when the tremor hit and thought it was a “practical joke” when he heard about the damage.
View this post on Instagram
No laughing matter
Australians are famous for making light of a serious situation, and Wednesday’s earthquakes were not off limits.
Social media users were quick to post photos of minimal damage caused by the trembling earth, along with the text: ‘We will rebuild’.
Some joked that Prime Minister Scott Morrison was again overseas during a natural disaster, while others poked fun at Premier Daniel Andrews.
The hashtag #IShakeWithDan began trending on Twitter on Wednesday afternoon, with some jovial users suggesting Mr Andrews had “flicked the earthquake switch” to prevent unhelpful protests across the CBD.
Others posted photos of some of Melbourne’s interesting architecture, suggesting it had been caused by the quakes.