Damage to land as well as property is complicating the insurance process for property-owners in and around earthquake-ravaged Christchurch.

The geography of Canterbury province was severely affected in both the September and February quakes, and work will be needed to stabilise land that has liquefied or moved before buildings can be repaired or rebuilt. Continuing aftershocks are further delaying the process.

The Canterbury Earthquake Recovery Authority (CERA) and Earthquake Commission (EQC) have begun a survey of damage to land resulting from the earthquakes.

The agencies and their geotechnical consultants are covering residential and commercial land, looking at the danger of rockfalls, the extent of liquefaction – where waterlogged soil becomes like quicksand – and lateral spreading, where land slides towards any nearby waterway.

Earthquake Recovery Minister Gerry Brownlee says he hopes to give indicative timelines on land remediation later this month, and CERA is aiming to outline where repairs can start on areas that have suffered minimal damage.

The survey will give insurers and their clients an indication of what is needed to restore damaged land and buildings.

In extreme cases it might mean some properties and parts of suburbs are abandoned because the cost of remediation is too high.

Remediation work to stop liquefaction and lateral spreading began after the September earthquake, and was expected to cost the Government $NZ140 million ($130 million). But much of this was undone by the February event.

Householders have some comfort because residential land around the house is insured through the EQC, but leading loss adjuster Martyn Norrie foresees disputes between insurers and clients over remediation on land used by commercial buildings.

Assessors still cannot get into the “red zone” in the heart of Christchurch because so many buildings are unsafe, Mr Norrie says, and demolition rather than remediation is the only work taking place so far. 

Mr Norrie, CEO of Cunningham Lindsey in NZ, says it is difficult for insurers to take a position without information from CERA and the geotechnical engineers. CERA aims to have all demolition work completed by June and the city centre open to the public on October 29.

The industry is also awaiting a decision on building codes and expects these will be much tougher for rebuilding.

“Land is still shaking and many of the repairs done after the September earthquake were undone in the February earthquake,” Mr Norrie told insuranceNEWS.com.au.

He says some minor repairs are going ahead “but if you are getting aftershocks, you may be throwing good money after bad”.

Insurance Council of New Zealand CEO Chris Ryan says the industry is awaiting reports on land as well as local authority decisions on tougher building regulations.

“Once we get clarity we can start to move forward,” he says, adding that insurers will also then be able to discuss losses with reinsurers.

Although the land reports may be ready within the month, Mr Ryan says little rebuilding can be done until the aftershocks stop.

Misko Cubrinovski, Associate Professor in the Department of Civil and Natural Resources Engineering at Canterbury University, is an expert on liquefaction and says it could take a couple more months to survey ground conditions and determine the remediation needed. 

He told insuranceNEWS.com.au the quake has exposed the weak points and there is a range of remedial actions to repair soils and make them more resistant to liquefaction recurring. These include adding a cement-like binding agent or improving drainage.

Professor Cubrinovski says soils and building foundations can be strengthened against future expected events, but soil quality and the extent of damage will determine whether a regional or site-by-site approach to remediation is needed.