An earthquake engineer has told the Canterbury Earthquakes Royal Commission the intense vertical shaking of the February 2011 earthquake was not unique.
The hearing is investigating why the CTV building collapsed, killing 115 people.
According to a Department of Building and Housing report critical of the building, it was subject to one of the highest levels of vertical acceleration recorded in any urban environment.
However, Brendon Bradley, who lectures at Canterbury University, says that despite the unique failure of the building itself, the vertical jolt was nothing new.
Dr Bradley says similar effects have been recorded during several overseas quakes.
Earlier a geotechnical engineer told the commission that soft soil at one part of the CTV site could have caused extra stress on the building during an earthquake.
Tonkin & Taylor principal Tim Sinclair said that before the building was constructed in 1986, bore holes showed a layer of gravel about four metres down throughout the site, except in the north-east quadrant.
Mr Sinclair said the softer soil could have added stress to the foundations during a quake.