Seismic risk standard for Canterbury not updated. Ministers deny awareness.

To whom it may concern:

This is to notify aspects of fundamental mismanagement on the part of the recovery authorities in Christchurch.

The seriousness of this matter is such that it could lead to another disaster in the future in Christchurch.

It appears that the NZS1170.5 standard has been left unchanged after the earthquakes. This is one of the most important documents for the rebuild, as it should include the increased seismic risk. This document defines the minimum strength for foundations and ground bearing. While it may be lawful to leave this standard as is, it is unethical to allow building on unsuitable land with foundations that are much too weak. This is potentially a pre-designed man-made future disaster for Christchurch.


70 Recommendations from the Royal Commission have been accepted by the government as at Sept 2012. But they have not been implemented.




The standard remains unchanged.


This standard is referred to in the Geotechnical Engineering Practice – Module 1 – Guideline for the identification, assessment and mitigation of liquefaction hazards. Geotechnical engineers are encouraged to follow this outdated load-bearing standard.



While the MBIE guides include SLS and ULS references, they are only guidelines that are not enforceable. NZS1170.5 is the applicable standard and it remains incorrect but enforceable.

According to LAW, the calculation references for ground shaking are SLS 0.06 g and ULS 0.25 g.

According to GNS Science and the Royal Commission, these should be significantly higher.

MBIE gives one reference for SLS of 0.13 while other SLS references are still to be announced.


MBIE published the following document in February this year.


  • Structural performance standards and practices: incorporating learning from the Canterbury earthquakes into the Building Code (specifically clause B1 Structure, and its supporting documents, particularly NZS1170.5 and NZS3101) and engineering design practices, to enhance and provide confidence in the structural performance of future buildings in New Zealand

These are fundamental documents that have been left as they were before the earthquakes. Leaving the update of these documents so late could be construed as wilful negligence on the part of the government.

At the Press debate on 4 September, John Key made the statement that 90% of claims had been settled. If the calculations for the settlement of these claims were based on NZS1170.5, ground bearing and foundations are likely to be well below requirements. This is a very serious issue that could potentially have dire consequences for Christchurch.

At a public meeting on Saturday, I specifically asked the Minister for the Earthquake Recovery, Gerry Brownlee, about the NZS1170.5 standard and why it had not been updated.

He replied that “all standards have been updated”. (Recording is available).

I asked Standards New Zealand about NZS1170 last week, and they confirmed that this standard has not been updated since the earthquakes.

This explains some of the highly dubious practices that are currently being witnessed in Christchurch.

Considering the amount of structural work that is allowed to take place in Christchurch as exempted from a building consent and therefore inspections. I regard this situation as a high probability of misuse of the current incorrect standards.

MBIE has identified this ambiguity as follows.

“Voluntary guidance could remedy these problems to some extent; however, leaving the supporting documents unchanged would see a conflict between them and the guidance. This would reduce the clarity of what is required for Building Code compliance.

Furthermore, the purpose behind setting appropriate seismic risk hazard requirements is to protect lives and property. Guidance is not normally used to achieve these critical objectives.

The option of publishing guidance would therefore not resolve the identified problems.”


Insurance claims are likely to be settled by legal definition if that is more affordable than using guides.


I would ask that this matter be given urgent priority and that standards be corrected to reflect the current situation here in Christchurch.


Hon Nick Smith, Minister for Building and Construction has denied any awareness or communications with GNS on this issue.
Attached see a letter in response to an OIA request in this regard.

One Comment
  1. We have some positive reaction. Standards New Zealand have just announced a proposed update of 1170 Structural Design Actions – Part 5 amendment to supplement and standard. While the standard is not in place as of now it is at least in progress. Things will progressively get better. While it has been painful to be dragged on year after year having correct standards in place gives a bit more certainty about the future.
    Here is hoping for a quick implementation.

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