Seismic Risk Assessment in New Zealand — What It Involves and What Comes Next

A seismic risk assessment tells a building owner how much an earthquake could cost them — in damage, downtime, and danger to occupants. If you have been asked to commission one, or you are weighing whether your building needs it, here is what a seismic risk assessment in NZ actually involves and what usually follows.

Seismic risk assessment vs seismic hazard analysis

The two terms are often used interchangeably, but they answer different questions.

Seismic hazard analysis looks at the ground. It estimates how strongly a site is likely to shake, based on nearby faults, soil conditions, and return periods. It is site-specific and largely independent of what you build there.
Seismic risk assessment looks at the consequences. It combines that hazard with your building's vulnerability and the value of what is inside — people, equipment, operations — to estimate likely losses.

Put simply: hazard is the shaking; risk is what the shaking does to you.

What a seismic risk assessment typically covers

Scope varies with the building and the assessor, but most assessments consider:

Structural vulnerability — how the building itself is expected to perform, often expressed as a percentage of New Building Standard (%NBS).
Non-structural elements — ceilings, partitions, and building services that can fail or fall even when the structure holds. NZS 4219 governs the seismic restraint of these services.
Contents and equipment — plant, stock, and specialist gear that may be worth more than the structure itself.
Occupant safety — injury risk during and immediately after shaking, including secondary hazards such as fire.
Business continuity — how long operations could be interrupted, and what that interruption costs.

From assessment to mitigation — where gas isolation fits

An assessment that only produces a number has limited value. The point is to guide mitigation: strengthening, restraint, or active controls that reduce the identified risk.

Gas is one of the clearest secondary hazards an assessment surfaces. Shaking can crack pipework, dislodge fittings, and leave gas flowing into a damaged building — a fire risk at exactly the moment it is hardest to respond to. Automatic isolation removes the dependency on someone being present to shut the supply off.

The Solid State Seismic Shutoff — MK6 addresses this directly. It is an electronic trigger, not a mechanical valve: it detects the P-wave that arrives ahead of the destructive shaking and fires its output relay within 10 milliseconds, isolating the gas supply before the worst of the quake hits. It records every activation, and five sensitivity settings let it be tuned to the site — the same site-specific thinking a good risk assessment applies. Designed and made in New Zealand since 1971.

Next steps

If a seismic risk assessment has flagged gas or fire as a residual risk, automatic isolation is a targeted, low-cost mitigation. To discuss how the MK6 fits your building — or to specify one into a wider seismic upgrade — get in touch. You can also read more on what New Zealand's seismic zones mean for your building.