There's now been three reported tremors in the Hunter Valley.
The latest was 2.7 magnitude tremor hit southwest of Warkworth.
It follows a 2.8 magnitude south of Muswellbrook just before midday, and a larger 3.4 quake at 11:23am.
The earth's been moving in the Hunter Valley this morning.
According to Geoscience Australia, a 3.4 magnitude quake struck just south of Muswellbrook at 11:23am.
It measured about 3km deep.
The epicentre appears to be the Mt Arthur mine.
There are no reports of any damage.