NZ a world leader in quake design

New Zealand is one of the world's leading authorities in earthquake design but as the devastation from the Christchurch quake…

New Zealand is one of the world's leading authorities in earthquake design but as the devastation from the Christchurch quake testifies, it is virtually impossible to make buildings completely quake-proof.

In a country well-versed in coping with earthquakes, it has been Christchurch's older buildings that have come off worse. The city is well-respected as a study centre and pioneer in earthquake engineering. But despite this, images have revealed the quake's unstoppable trail of destruction.

The city's cathedral has been left spireless and badly damaged and the modern four-storey Pyne Gould Corp building has collapsed in on itself.

Professor Colin Taylor, who is professor of earthquake engineering at the Department of Civil Engineering at Bristol University, said modern buildings were now designed to "fail in a controlled way".

"From the pictures I've seen, the majority of the buildings that have been damaged date from the 1970s and 1980s," he said. "This was a time when earthquake design was still very primitive. The more modern buildings would have performed much better.

"A lot of damage seems to have been caused from facades that have fallen from buildings. This is typical of older buildings."

He said universities in the area had pioneered work on capacity design - engineering that enabled buildings to withstand quakes. "Buildings are now designed to fail in a controlled way. You design the building to be strong enough to survive the earthquake," he said. "But you can never make a building entirely earthquake-proof."

The Christchurch quake measured lower on the scale than the earthquake that struck the city last September. The latest earthquake caused far more damage as its epicentre was much nearer the city.