Earthquake Prone Building Policy
New Zealand has a relatively high earthquake risk – so it is important for safety reasons that buildings are built or upgraded to be safe in a ‘quake. This page introduces the Earthquake Prone Building Policy.
Introduction and background
Section 131 of the Building Act 2004 requires territorial authorities (TAs) to adopt a policy on Dangerous, Insanitary and Earthquake-prone buildings as of 31 May 2006. The Policy must also state how it applies to heritage buildings.
The definition of an earthquake-prone building is set out in section 122 of the Building Act 2004 and in that related regulations that define moderate earthquake. This definition covers more buildings and requires a higher level of structural performance of buildings than that required by the Building Act 1991.
A building is earthquake prone for the purposes of the Act if, having regard to its condition and to the ground on which it is built, and because of its construction, the building—
- will have its ultimate capacity exceeded in a moderate earthquake (as defined in the regulations); and
- would be likely to collapse causing—
- injury or death to persons in the building or to persons on any other property; or
- damage to any other property.
However, the definition does not apply to a building that is used wholly or mainly for residential purposes unless the building comprises two or more storeys and contains three or more household units. Council's policy does not apply to these buildings, such as ordinary residential homes.
The government has, in regulations, defined a moderate earthquake as ‘in relation to a building, an earthquake that would generate shaking at the site of the building that is of the same duration as, but that is one-third as strong as, the earthquake shaking (determined by normal measures of acceleration, velocity and displacement) that would be used to design a new building at that site’.
The policy was adopted by Nelson City Council in accordance with the requirements of the Building Act 2004.
In developing and adopting its earthquake-prone buildings policy, Nelson City Council has followed the special consultative procedure set out in section 83 of the Local Government Act 2002. Nelson City Council has made extensive use of the Department of Building and Housing’s guidance document.
Administering the policy is a regulatory function of the Council in it's role as a territorial and Building Consent Authority. It is carried out by Council's Building Unit.
Download the Earthquake Prone Building Policy (114KB PDF). Please note, Nelson City Council’s Chief Executive announced in March 2014 that buildings identified as earthquake prone will only be required to be strengthened to no less than 34% NBS).