Three earthquakes - including a magnitude 5.8 shake - have rattled Melbourne this morning with reports of damage in the city and across Victoria. See how today's events unfolded with RNZ's blog.
Geoscience Australia said the earthquake was 10km below the surface about 150km east of the city.
The initial quake was felt 190km away in Melbourne, as well as in regional Victoria, Sydney, regional New South Wales, the ACT, Adelaide and Launceston in Tasmania.
Geoscience Australia said the quake was potentially the largest earthquake in eastern Australia, at least since European settlement.
A magnitude-4 earthquake was recorded by the agency nearby about 15 minutes later.
There has been minor damage to around 46 buildings across the state but no reports of injury.
Tremors were felt as far away as New South Wales and Adelaide.
See how the day unfolded with RNZ's live blog:
NZ's GeoNet said for an earthquake of this depth and magnitude, there would have been strong shaking, particularly close to the epicentre near Mansfield.
"This is the largest on land earthquake in Australia since 1997. Earthquakes in Australia are reasonably uncommon, being far from the active tectonic zones of the Australian plate."
Geoscience Australia said the quake was detected around Mansfield in Victoria's north-east and hit at 9.15am local time.
Apartment buildings are being evacuated in inner Melbourne, where damage to streets and roads is being posted to social media.
Windows buckled as quake shook Mansfield
FoodWorks Mansfield assistant manager Karen McGregor said she first thought a truck was coming into town.
"The windows started shaking, the walls, and everything on the desk, it was really quite scary," she said.
"We ran downstairs to the shop, it was really, really scary down there. The windows were buckling.
"I was very scared. I just thought, oh my God, is this place going to fall down?"
McGregor said she had not heard reports of anyone with any injuries.
Despite the shaking, she said the shop did not sustain too much damage, with only a few unbreakable items off the shelves.
Chapel Street pic.twitter.com/zrijYmB6qO— Paul Dowsley (@paul_dowsley) September 21, 2021
Some major damage to a building on Chapel Street following the earthquake. pic.twitter.com/FiIlv9Zxmf— Georgia Bennett-Murphy (@georgia_bm_) September 21, 2021
Region: Mansfield, VIC— EarthquakesGA (@EarthquakesGA) September 21, 2021
UTC: 2021-09-21 23:33:38
Lat: -37.48, Lon: 146.30
For more info and updates, or if you felt this earthquake, go to https://t.co/r8gjDuMdZ2
Ross, 60, who lives on the Bellarine Peninsula told ABC Radio Melbourne it was the biggest earthquake he had ever experienced.
"We've just moved into a round earth house on a concrete slab and the whole thing just rock and rolled and the water in the swimming pool went sloshing backwards and forwards," he said. "I couldn't believe it."
Margot in Moonee Ponds said at first she thought her daughter was pranking her when her whole house began shaking. "It was quite intense," she said. "My chair was shaking… everything in the room was rattling and clinking together."
Expert says aftershocks could continue for months
Seismology Research Centre head Adam Pascale said the epicentre of the quake was north-east of Aberfeldy and the Thomson Dam in the Alpine National Park.
"We are still refining it, but we think it's a magnitude 5.8 potentially at this point in Gippsland," he told ABC Radio Gippsland.
"It shook here in the northern suburbs of Melbourne for about 15-20 seconds so it's quite a significant earthquake."
Pascale warned there could be aftershocks to come and they could continue for months.
"There is a small likelihood that there could be a larger event but we'll see as we go," he said.
"The main things for people to remember is if they do start to feel some shaking. There's usually a primary and a secondary wave.
"The primary wave will give you a few seconds to get under a table and hold on."
- RNZ / ABC