Another earthquake as strong as one that killed 13 people in 1989 could hit Newcastle, according to catastrophe modeller Risk Frontiers.

Speaking at a seminar in Sydney last week marking Risk Frontiers’ 20th year of operation, Chief Geoscientist Paul Somerville said Newcastle remains vulnerable to another direct hit on the CBD.

“There have been other quakes near Newcastle and we are not sure that this cluster of quakes is over yet,” he said.

Professor Somerville predicts that if another quake hit today, the damage bill in Newcastle would be at least $3 billion, compared with about $4.3 billion (adjusted for inflation) for the 1989 event.

“We have a fault under the city and the CBD is sitting on top of it.”

The 1989 quake reached up to magnitude 8 in the centre of Newcastle, Professor Somerville says.

About 35,000 insurance claims were lodged, with 300 buildings demolished, including more than 100 homes. Damage occurred to 147 schools, 3000 commercial and other buildings and 35,000 homes.

“The Newcastle event had some similarities to the Christchurch quake in the sense of coincidence of the earthquake shape and footprint in the CBD,” Professor Somerville said.

He says Sydney is also at risk from quakes, although a direct hit on the CBD is unlikely, with the city’s west along the Lapstone fault most vulnerable.

“We are now assessing whether [the fault] is active. It does seem to be associated with fairly frequent smaller earthquakes, but we don’t yet know if it can still generate big ones.”