'Years' before all jolt prone sites known

Not all buildings have been properly assessed. Photo / Doug Sherring

Aucklanders will know by Christmas which hospital and other emergency buildings are earthquake-prone, but it could be years before they know if their local cafe could tumble and kill in a moderate shake.

Auckland Council officers are busy assessing hospitals, police stations and public buildings that would be required in the event of a catastrophic earthquake.

But it will be up to politicians to develop a regionwide earthquake-prone policy for most commercial buildings.

A report exclusively obtained by the Weekend Herald showed that many of Auckland City's old town centres are studded with 393 earthquake-prone character buildings, but little or no work has been done in other at-risk suburbs, such as Devonport and Birkenhead.

Last night, civil defence manager Clive Manley said he could not tell Aucklanders when a regionwide list of earthquake-prone buildings would be completed and made public.

That was because Auckland councillors still had to develop a policy setting the bar for strengthening buildings and how long owners had to upgrade buildings.

Mr Manley said the Wellington City Council had estimated it would take more than four years to assess buildings, but he acknowledged that an Auckland regionwide list could be drawn up much faster if there was the political will and resources to do so.

One factor that could speed up work was higher public interest sparked by the Christchurch earthquakes, he said.

Auckland City appears to be the only former council in the region that drew up a register of earthquake-prone buildings - and that register was preliminary.

It was a list of buildings that could be susceptible to earthquake damage and not all the buildings had been properly assessed, according to council officers.

Other Auckland councils appeared to put the need for a policy - as required under the Building Act 2004 - on the backburner given Auckland's low earthquake risk.

A draft earthquake-prone building policy issued by the former North Shore City Council in 2006 estimated there would be fewer than 200 buildings affected by the policy, mostly in Devonport, Birkenhead and Takapuna.

Instead of taking a passive approach of assessing the earthquake risk of buildings when an application was made to renovate or alter them, the North Shore council decided to take an active approach requiring owners to investigate and propose remedial works of buildings deemed by the council to be potential seismic risks.

The Building Act requires earthquake-prone buildings to be strengthened to 33 per cent of the design level of a new building.

The act defines earthquake-prone buildings as those likely to collapse in a moderate quake, causing injury or death, or damage to other property.

The draft North Shore policy recommended doubling the minimum strengthening work for some buildings, including hospitals and those such as bars and restaurants that drew big crowds, to 67 per cent.