Radio New Zealand

The Royal Commission on the Canterbury earthquakes has been told the Christchurch central city has soil that is very susceptible to liquefaction.

The commission has begun hearing evidence about the soil types in the central city and how they may have contributed to building failure.

On Tuesday morning it heard evidence from Associate Professor of Civil and Natural Engineering Misko Cubrinovski.

Professor Cubrinovski says much of Christchurch's central city has a high water table, a sandy composition and is young in geological timeframes.

He says parts of the city centre have reasonably soft soil up to seven to eight metres deep and this will require special attention in terms of foundation design.

Professor Cubrinovski says overall the conditions for building foundations are very complex and challenging for geotechnical engineers, particularly in terms of their performance during strong earthquakes.

He told the Royal Commission there is no specific foundation he would recommend for earthquake-prone areas and it would depend on site specific investigations into the land and the design of the building.

He says, however, he would like to see more tests carried out before construction starts.

The Royal Commission also heard from civil engineer Jonathon Bray, who carried out a peer review of Professor Curbrinovski's report.

He said California now required tests to be carried out before construction and this did not appear to have resulted in additional costs,

It saved money in the long run, he told the Royal Commission, by making the buildings more quake resistant.

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Extra time for quake paperwork

People in Canterbury who want their earthquake contents claims paid out by Christmas have been given an extension of the deadline to send in their information.

The Earthquake Commission had guaranteed that all claims sent in by Monday 25 October would be paid out by Christmas.

It has now given people until Friday to get all the necessary paperwork in.

EQC says anyone who puts in a claim after then will still be paid but it may not be until next year.