Seismicity of NSW and the A.C.T.
NSW largest earthquakes.
The largest earthquake in NSW since 1900 was the 1961 Roberstson earthquake (magnitude 5.8), which was felt strongly in the Bowral region, and also in Sydney. It was the largest of several large earthquakes originating from within the Sydney (Geological) basin.
The most significant of the Sydney Basin events was the magnitude 5.4 Newcastle earthquake in December 1989. This event caused extensive structural damage throughout Newcastle and beyond, and resulted in the deaths of 13 people.
Also in the Newcastle area, slightly larger, but not so damaging, was the magnitude 5.3 Ellalong earthquake 5 years later, in August 1994.
A magnitude 5.3 event near Picton in March 1973 was followed by a very long sequence of aftershocks.
Very recently, a magnitude 4.8 event near Muswellbrook also resulted in a long sequence of relatively large aftershocks. From its location, very close to a coal mine, this event is possibly – or probably – mining-related (as was the Ellalong event of 1994).
Many of the larger events in NSW occur along the region of the Great Dividing range, and particularly in the Snowy Mountains region. A magnitude 5.6 event near Dalton (~70 km north of Canberra) in November 1934 caused considerable local damage, and the area remained seismically active for many years afterwards.
Quite a few relatively large earthquakes have been recorded from the far northwest of NSW. The largest of these was probably a magnitude 5.1 event, about 150 km north of Wilcannia, in August 1996.