30 homes in anti-liquefaction pilot
The number of Canterbury properties with increased liquefaction risk will not be known before May, the Earthquake Commission (EQC) says.
However, it says the results of a ground improvement pilot programme will make settling some land claims - mainly technical category 3 - easier.
EQC chief executive Ian Simpson said at last week's Seismics in the City conference an EQC-led research programme to find cost-effective solutions to strengthen residential land had attracted international interest.
Explosive testing in the residential red zone last year helped to develop engineering solutions to improve land with increased liquefaction risk.
About 30 properties in Kaiapoi and Christchurch are now part of a pilot programme where methods are being used "under real homes, in real streets, in real neighbourhoods", Simpson said.
The programme will help EQC tackle land claims by putting a price tag on the cost of remediating land vulnerable to liquefaction.
"People will be talking about this for years because we're taking a measured amount of time to rebuild better," he said.
EQC was unable to provide the total number of land claims in the increased vulnerability to liquefaction category.
Hugh Cowan, EQC's reinsurance, research and education manager, told The Press last October that figure would be known in December.
An EQC spokeswoman said this week engineering analysis would be complete this month but EQC was unlikely to be able to confirm numbers until May.
EQC would advise homeowners if their properties wereincluded but engineering consultants Tonkin & Taylor had already indicated a small number of properties might require additional investigation, he said.
Cowan said improving the performance of land meant it would be more resilient in major earthquakes in the future
"It means the effects of liquefaction will be reduced."
There were two advantages from a building point of view, he said.
"First, lighter and less expensive foundation solutions may be used. Second, the land will not subside to the same extent and, if it does, subsidence will be more uniform and properties will be able to be repaired more easily."