GEOSCIENCE Australia has confirmed three earthquakes hit the Hunter's coalfields within a few hours overnight.
Subscribe now for unlimited access.
$0/
(min cost $0)
or signup to continue reading
Duty seismologist Eddie Leask said the third quake hit about 1am with a 2.0 magnitude.
It followed two earlier quakes within moments shortly before 10pm on Tuesday in the same area with magnitudes of 3.0 and 3.1.
"It could have ruptured the surface but it's unlikely," Mr Leask said.
"People would have definitely felt it but it's pretty unlikely you would have damage to local properties [solely from the quake]."
While initial reports put the epicentre off the Newcastle coast, it was later clarified to an area to the east of Cessnock.
The largest of the quakes could be felt about 25km from where it struck, Geoscience Australia reports.
Mr Leask said that while mining and earthquakes often coincided in similar areas due to pressure build-up, there was no definitive link between mineral extraction and earthquakes.
"It's a convoluted question," he said.
The quake follows small tremors in recent years including one 10km from Cessnock in August detected by a sensor array based in Coonabarabran.
That earthquake measured 2.4 on the richter scale while a 2.5 magnitude quake struck Harrington, near Taree, later that month at a depth of one kilometre.
Mr Leask said smaller tremors were no more an indication a larger quake was on its way than their absence.
"It's possible that we could be on the way for a large event but there's no way to know," he said.
Physicist Dr Michael Phillips from Coonabarabran’s Edward Pigot Seismic Observatory (EPSO) said the tremor, the second near Cessnock in less than two months, was not particularly unusual.
‘‘The whole Newcastle area is quite hot by Australian standards,’’ he said.
Dr Phillips said that while the richter scale reading gave an indication of the energy expelled through the quake, it was the depth at which it occurred that determined how much it was felt.
‘‘A magnitude three near the surface should be felt, it should be a china cabinet tinkler for sure,’’ he said.
‘‘It’s very dependent on depth though, because you could have an absolutely enormous earthquake at considerable depth and you might not feel anything.’’
