Let’s stop this nonsense of thinking we have to earthquake-safe most of our older buildings.

At the same time, remove the notion that a building of say 34% NBS (that is, 34% of a new building of at at least 100% NBS) is unsafe. 

Such buildings aren’t dangerous as such. They’re fine – or even more precisely, fine enough.

No one will disagree we don’t want people killed in buildings (specifically commercial buildings…homes have no rules at all really) as a result of an earthquake.

A 34% NBS-rated building, in a good shake, even a good shake, will keep its people inside alive.

The building might be a mess, but its occupants will be OK.

To repeat. A 34% NBS building allows people to get out alive.

The trick is that the interpretation of the Building Act and Health and Safety Act, and particularly the Building (Earthquake-Prone) Amendment Act 2016, has been left up to individual territorial authorities such as Wellington City Council.

This means different judgments across New Zealand.

Throw in a misinterpretation that building owners are liable for people getting hurt in the event of an earthquake.

As a paper presented at the 2021 NZ Society for Earthquake Engineering points out, this has led to huge inconsistencies, exaggerated fears, and huge costs that simply don’t need to happen.

The multi-authored paper says in its abstract: “A common misconception in some sectors is that if a building is rated as less than 34%NBS and/or declared earthquake-prone, then the building is dangerous and should be closed immediately. This has led to long periods when public facilities and services are not available to local communities, resulting in some notable socio-economic impact.”

What is notable is that the enforcer of the rules, MBIE is extremely keen to dampen emphasis on NBS ratings. An excellent article (Seismic Risk Guidance for Buildings – ‘Keep Calm and Carry on’) by lawyers Dentons Kensington Swan points out that understanding the relative vulnerability of different building elements and potential consequences of failure is always more important than the overall %NBS for a building.

The Denton article notes that MBIE reminds us that earthquakes are rare and the risk of a fatality due to building failure in an earthquake is lower. A 100%NBS new build is designed with a 1 in 1,000,000 annual fatality rate. An earthquake-prone building (<34%NBS) is estimated to have a 1 in 40,000-100,000 annual fatality risk. This compares to the risk of aeroplane travel (1 in 700,000) and car travel (1 in 20,000). Is anyone for banning cars as a result?

As we can see in the plethora of yellow-stickered buildings around Wellington, knee-jerk reactions to seismic assessments including vacating premises and/or terminating leases, have made for an uneasy property market.

But…in the event of an earthquake, occupants in those 34%NBS and fewer buildings will almost invariably get out alive.

Our territorial authority, Wellington City Council, can tweak how it interprets various Acts.

For the health of our city, WCC could, through a more nuanced application of MBIE’s guidance, revitalise our vacant buildings that are perfectly safe in the overall scheme of things.

AI generated image showing Wellington city from the water angle after an 8.9 earthquake

In a hypothetical scenario where Wellington is cut off from New Zealand, the financial damage could be significant, potentially involving billions of dollars in economic losses due to disrupted trade, transportation, and infrastructure. Estimating precise figures is challenging and would depend on various factors such as the cause and duration of the isolation. Additionally, the loss of life could occur, but the extent would rely on factors like available resources, emergency response effectiveness, and specific circumstances. Overall, preventing and preparing for such events are crucial for minimizing both economic and human losses.

“About the Author”

Peter Kerr, Marketing Manager at Pertronic Industries, is a master storyteller known for his ability to distill complex concepts into compelling narratives. With expertise in crafting Million Dollar Messages and simplifying technical content, Peter empowers businesses to communicate with clarity and impact. Through Punchline, he offers writing training and specializes in creating persuasive copy for various platforms.