Victoria records quakes, but not many shakes

The seismologist said there were 122 small quakes, in total, registered for that particular week (late in August).

“We probably have 30 or so, on average, a week. But unless they are in excess of a three (on the Richter scale) people will not even know they are happening,” he said.

The Riv made contact with Mr Pascale after our regular perusal of the archives at the Echuca Historical Society brought the events of September, 1981, to our attention.

Our region was a hive of activity after an earthquake measure three on the Richter scale was recorded 50km north of Echuca, at Bunnaloo.

Cups and saucers were hardly falling from kitchen benches, but it was the news of the day as the front page headline read ‘Earth tremor shakes Bunnaloo . . . New check on local quakes'.

A close friend of Mr Pascale, Vaughan Weston, was quoted in the article as suggesting recording equipment would be installed in the region as a result.

Mr Weston was working from the then Preston Institute of Technology’s seismology department, which — funnily enough — is the predecessor of the organisation now headed by Mr Pascale.

“We started monitoring local earthquakes in 1976, so we only have a few small events listed near Bunnaloo before that magnitude 3.1 earthquake,” Mr Pascale said.

But it hasn't quite been ‘all quiet on the Western Front’, as the 1980s saw regular minor events before things slowed considerably.

“We’ve recorded a total of 150 (earthquakes) within 20km of that event, mostly between 1981 and 1992,” Mr Pascale said.

“The latest earthquake, in the immediate area, was a magnitude 0.9 in July 2021, but we’ve seen fewer than one a year in that area for the last 20 years."

Mr Pascale said earthquake records dated back to the late 1700s, but before 1960 most of these events were only reported if they were very large and near populated areas.

“Often they were added to the catalogue based on reports found in newspapers,” he said.

“We have fewer stations in western Victoria than we used to, the funding for extra stations back in the 80s and 90s ran out years ago.

“The only station of that original network remaining is at Mt Hope (between Pyramid Hill and Leitchville).

“We used to have stations at Rushworth, Buckrabanyule, and one near Bunnaloo,” he said.

The SRC network is designed to provide an earthquake notification service for private industry, funded by operators of large infrastructure that require rapid information for emergency response.

“We also design and develop the earthquake monitoring instruments and analysis software here in Melbourne,” Mr Pascale said.

The seismology centre’s chief scientist told the Riv last week that his last visit to Echuca was after the 2008 quake, which registered 3.4 on the Richter scale.

“I came up and installed a couple of extra stations. But since then there has not been a lot of activity,” he said.

Mr Pascale, who has been working in the field for 30 years, said activity on the earthquake front in south-east Australia was reasonably consistent.

“Seems to be 30 or 40 on average that we locate each week. That’s a lot more than you will see from Geoscience Australia, who deal only with larger quakes,” he said.

“We have a higher density of equipment and go down to as small as we can see.

“We then post everything.

“We are seeing all of the tiny little events. Anything below magnitude two is unlikely to be felt; even a magnitude three might not be felt.”

Echuca is far from the most active part of Victoria and NSW — that is generally the Great Dividing Range, from Gippsland to the Southern Highlands of our neighbouring state.

Mr Pascale said seismographs did operate throughout the region and needed to be nearby to detect any tremors.

“We generally place them on someone’s property,” he said. "Usually on some hard rock, which farmer’s don’t mind because they can’t use the land for much else.”