On December 28, 1989, an earthquake measuring 5.6 on the Richter scale struck at 10:27 am, local time.
The epicentre was calculated to be at 32.95 degrees south latitude and 151.61 degrees east longitude, placing it a little to the west of the Lake Macquarie suburb of Boolaroo.
The focus was at a depth of 11.5 kilometres, very shallow, when the rocks beneath the overlying Permian sediments and Carboniferous rock ruptured. The epicentre was approximately 15 kilometres from the Newcastle CBD and 24 kilometres from central Maitland.
The earthquake devastated parts of Newcastle, particularly buildings in Hamilton, Broadmeadow and Newcastle West. There were 13 fatalities in Newcastle and about 160 people suffered injuries which required hospitalisation.
Throughout Newcastle and Lake Macquarie about 40,000 homes were damaged and about 10,000 commercial and other buildings (including 147 schools) suffered a similar fate.
By the end of 1990, 167 buildings had been demolished. The worst-hit building was the Newcastle Workers Club, where the internal structure collapsed, resulting in nine deaths.
Three people were crushed to death by falling masonry in Beaumont St, Hamilton, and a person later died from shock brought on by the earthquake.
Maitland, almost directly north of the epicentre suffered very little damage in comparison to Newcastle. There were no fatalities, but some masonry buildings suffered minor cracking.
The carpark beneath the Kmart store sustained some cracking to the brickwork, but it was later deemed to be structurally sound. In the City Council's administration building some ceiling panels fell and a piece of decorative stonework fell from the Town Hall's clock tower.
The City Engineer inspected local public buildings and bridges for structural damage. All were deemed sound.
During the quake, people ran from shops in panic and electric power failed, disrupting traffic lights and communications.
The worst damage was to Mansfield House, at that time the home of the National Australia Bank (formerly the Commercial Banking Company of Sydney) in eastern High Street.
The Sydney architect, George Mansfield, designed the building, which was constructed in 1887. Its ornamentation included two decorative sandstone urns adorning the parapet above the main entrance.
During the earthquake, the urns broke off and tumbled to the ground. It was fortunate that nobody was standing beneath them as they fell.
The urns smashed the concrete pavement and lay half buried in the footpath from the momentum of the fall.
The urns are still in existence.
They were removed from their resting place on the footpath and taken to the rear of the building.
They now reside in the garden at the rear of Mansfield House and are unlikely ever to be reinstalled in their original positions.
A team from the Australian Seismological Centre in Canberra, was sent to set up seismographic recorders in Newcastle immediately after the quake.
A single aftershock, with a magnitude of 2.1, was detected at the Boolaroo location of one of these recorders the next day at a focal depth of 13.6 kilometres.
No damage was recorded. It was calculated that the earthquake itself had an energy equivalent of 50,000 tonnes of TNT.
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