Concerns about quake-proofing Canterbury

Workers make emergency repairs to a building in Central Christchurch following the earthquake. Photo / Greg Bowker.

Canterbury's 7.1 magnitude earthquake earlier this month was not the predicted "big one", and more work needs to be done to improve building codes to prevent greater damage in another earthquake, two University of Canterbury academics say.

The earthquake on September 4 caused widespread damage to buildings and infrastructure in the region, but a lot of buildings have survived despite the large magnitude quake.

The level of ground shaking was only about 60 per cent of what buildings were designed for, and lower than it would be in a bigger earthquake, said Professor Andy Buchanan and Associate Professor Greg MacRae from the university's College of Engineering.

"Our concern is that people are saying that the current standards are more than enough because everything survived so well, but there are others of us saying let's be very careful here because there is still a larger earthquake predicted," Prof Buchanan said.

The strengthened masonry buildings in Christchurch had survived well, while many unstrengthened buildings had suffered a lot of damage.

Concrete buildings generally fared well, although that would not be the case in a bigger quake, he said.

Research carried out at the university in earthquake-proofing buildings was a key factor in restricting damage in the city to a predicted $4 billion, Prof Buchanan said.

Researchers were trying to design and protect buildings so that they would withstand the biggest of earthquakes, and more research was needed.

More than 1700 of the nearly 61,000 insurance claims made for minor damage had been assessed and the first payments made, earthquake recovery minister Gerry Brownlee said today.

"This is an encouraging start to the recovery phase of our response efforts, but we know there are still people waiting for inspections and I want to assure them reinforcements are on the way," Mr Brownlee said.

The Earthquake Commission (EQC) currently has 158 people in Canterbury, which will rise to 283 by Sunday and eventually over 400.

Over 100 geotechnical engineers were reporting to the EQC every day, but it would still take time to get through the workload.

The focus was on streamlining the process to pay claims for house damage of between $10,000 to $100,000, and for claims over $100,000.

"For those with major damage to houses and land this process is somewhat contingent on getting a precise picture of the extent of land damage and options for the future use of that land," Mr Brownlee said.

Canterbury is still being subjected to a flurry of seismic activity nearly a fortnight after the 7.1 quake, with aftershocks of at least magnitude 3 striking today, and a 4.4 magnitude quake last night.

The Red Cross Canterbury Earthquake Commission has given more than $110,000 in emergency grants in the region this week to 44 households whose homes have been ruined by the quake.

The commission began receiving applications on Monday, and paid the first grants of up to $3000 a day later.

The funds come from the Red Cross Canterbury Earthquake Appeal, which has received $4.9 million on top of $5m from the Government.

Eligibility rules and application forms are available at www.redcross.org.nz/earthquakegrant.

Christchurch City Council is winding down its emergency operations centre and returning its services back to business as usual.

Council staff are only investigating properties that pose an immediate danger. Property owners need to seek independent advice about other buildings.

Some sewage was discharging into the city's waterway system, and people were advised to avoid any contact with waterways.

Police have issued another warning about people trying to take advantage of earthquake victims, including criminals dressing up in United States-style police clothing and pretending to be police officers.

There have also been reports of phone calls from people claiming to be officials from local organisations and government.

- NZPA