Scenario: Earthquake — Gisborne Magnitude 6.7
Strong shaking damages buildings and infrastructure
Understanding what could happen in an earthquake similar to this event provides information on how to be prepared and how to reduce risk.
| Probability of similar shaking in 50 years | Estimated damage costs | Estimated number of damaged homes | Duration of earthquakes | Number of large aftershocks |
| 40% | >$50m | 3000+ | 30 seconds | 2 |
- Probability of similar shaking in 50 years: 40 years
- Estimated damage costs: >$50m
- Estimated number of damaged homes: 100,000
- Duration of earthquakes: 12
- Number of large aftershocks: 2
What could happen?
This scenario explores what could happen if a magnitude 6.7 earthquake occurred off the coast of Gisborne Tairāwhiti. Strong shaking would be felt across Gisborne city and nearby communities for about 30 seconds. Over the following two days, two powerful aftershocks make any damage worse. The earthquake causes the ground in soft or wet areas near rivers to become unstable, making it sink or crack. Steep hills and cliffs experience landslides, which can damage homes, roads, and other buildings.
An earthquake like this has a 40% chance of occurring in the next 50 years. There have been 15 earthquakes above magnitude 6 in Gisborne Tairāwhiti since the year 1900, including the 2007 earthquake that this scenario is based on.
This probability is based on modelling in the New Zealand Seismic Hazard Modelopen_in_new, which was developed by scientists to calculate the likelihood and strength of possible earthquakes across New Zealand.
Read more about landslides, earthquakes, and liquefaction and how they can affect people and places.
Earthquakes can damage homes, buildings and land. Most homes in New Zealand are designed to withstand earthquake shaking, but older buildings could be more susceptible to damage. Brick chimneys and loose stonework may fall, and items on shelves and in cupboards, as well as some furniture, may shift or topple during shaking.
Soft, wet, sandy, or silty ground near rivers or old waterways may liquefy, making it sink or crack. Land on steep hills or cliffs might slip and damage houses.
Everyday services and activities may also be affected for a time. Power outages may occur for several hours, and phone, internet, water, gas, and sanitation services may be affected. Some roads may experience minor damage but are likely to remain usable. The central business district, schools, and community facilities may close temporarily while safety checks and building assessments are carried out.
By exploring the potential impacts and damage from earthquakes, we can understand ways to be prepared and reduce our risk from these types of natural hazards.
Councils and planners can use this information to identify the most at-risk areas to guide decisions on building consents, land use, and emergency response plans.
For residents, it is important to know what natural hazards your property is exposed to and take steps to prepare:
- Learn how to make your home safer from natural hazardsopen_in_new
- Check that you have the right insurance in placeopen_in_new. A home insurance policy may qualify you for natural hazards cover.
- Check your local council website for information about local hazards and emergency planning in your area.
Strong ground shaking can cause items to fall from shelves. After the 2007 earthquake, staff at HB Williams Memorial Library faced a large clean-up.
Photo: Tairāwhiti Emergency Management, Gisborne District Council
Kitchens and cupboards emptied during the 2007 Gisborne earthquake.
Photo: Tairāwhiti Emergency Management, Gisborne District Council
- Earthquake
- Gisborne