30/05/2026
Just when you thought the Tartwaup Fault had gone quiet, a magnitude 3.0 earthquake struck off the coast of Beachport in the early hours of this morning.
The epicentre was recorded at a depth of about 10 km beneath the seabed, approximately 61 km northwest of Mount Gambier. The tremor was too light to be widely felt, but it serves as a reminder that this ancient fault line is not entirely silent.
That was not always the case.
The largest known earthquake associated with the Tartwaup Fault was the Beachport–Kingston earthquake of 10 May 1897, estimated at about magnitude 6.5. Because earthquake magnitude is measured on a logarithmic scale, that event released roughly 178,000 times more energy than this morning’s magnitude 3.0 tremor.
The BIG one struck at about 2:25 pm local time, causing serious damage around Beachport, Robe and Kingston. It was also strongly felt in Mount Gambier, where banks, hotels, churches and other buildings were damaged.
The last major shake in the region occurred on 6 August 1948, with a recorded magnitude of about 5.5–5.6. Contemporary reports said it cracked buildings, rattled tall buildings in Adelaide, cracked the Beachport Post Office wall, and was felt in Mount Gambier for several seconds.
The 1897 event is generally regarded as South Australia’s largest recorded earthquake, and the third largest in Australia’s recorded history.
No doubt, even larger seismic events may have occurred during the region’s active volcanic period, some 5,000 to 6,000 years ago.