Volcanic Events in Hawke's Bay

To find out more about the hazards where you live, work and play, visit out hazard map portal

What warning will there be?

There is usually some warning from GNS Science of any increase in volcanic activity and an ashfall risks. 

GNS is responsible for monitoring volcanic activity and setting alert levels.  GNS sends out Volcano Alert Bulletins which summarise the status of volcanoes and volcanic areas, and whether activity is increasing, decreasing, or in a steady state. GNS notifies response agencies in New Zealand whenever the alert level changes, and what warnings and information need to go out to communities.

The GeoNet app will keep you up-to-date and notify you if GNS issue a new bulletin.

How do I get prepared?

The main risk in Hawke’s Bay is from falling ash. You can do many things to protect yourself and your family from the dangers a volcanic eruption can cause - learn more at Get ready

What to do when it happens and after?

What action you take will depend on where you are located – near a volcano or down wind and affected by ash.

• Listen to the radio or check the internet to keep up to date, as alerts are regularly issued.
• It’s best to stay indoors as volcanic ash is a health hazard, especially if you have respiratory difficulties such as asthma or bronchitis. Close all windows, doors and dampers, and turn off heat pumps or air conditioners, to keep volcanic ash from getting inside. 
• If outside at the time of eruption, seek shelter in a car or a building. If caught in volcanic ashfalls, wear a dust mask or use a handkerchief or cloth over your nose and mouth.
• Avoid driving as ash falls will reduce visibility and make roads slippery and unsafe.
• Disconnect drainpipes/downspouts from gutters to stop drains clogging.  If you use a rainwater collection system for your water supply, disconnect the tank.
• If you have to go outside, use protective gear such as masks and goggles and keep as much of your head and skin covered as possible. Wear eyeglasses, not contact lenses as getting ash in these can cause permanent scarring of your eyes (corneal abrasions).

Some other useful links

• IVHHN Recommended Masks
• Health Hazards of Volcanic Ash – a guide for the public, by the Cities and Volcanoes Commission
•  Impact of a Volcanic Eruption on Agriculture and Forestry in New Zealand
• United States Geological Survey’s paper outlines how to rehabilitate farms affected by ash.
• GNS Ash Impacts advice for roads, vehicles, water supplies and electricity

There are no volcanoes in Hawke's Bay, but the area has been affected by over 20,000 years of volcanic activity, mainly in the form of ash falls. The North Island of New Zealand has both a high density of active volcanoes and a high frequency of eruptions. Five of these volcanoes have erupted, often repeatedly, in the past 300 years. The Hawke's Bay region is particularly vulnerable because the prevailing winds are from the south and west.

Scientists advise that eruptions from the Okataina and Taupo volcanic centres may produce sufficient volcanic ash to have significant impacts on Hawke's Bay. Large eruptions from Ruapehu, Tongariro, Ngauruhoe and Taranaki may also produce enough ash to impact on the region but will have a lesser impact. Eruptions from White Island and other volcanoes are not likely to affect Hawke's Bay.

Eruption Impacts

The impacts from ashfall vary with the thickness of ash and the type of ash. Mainly it’s fine, easily transported ash that will reach the region. The major problems from fine ash are likely to be interruption or failure of lifeline utilities, including transport and clean up costs. If ash is more than a few millimetres thick, disruption to traffic is likely as road markings will be covered, road surfaces will be slippery and vehicle air filters will get clogged. Airports may be closed, disrupting national travel.

Check out the GNS Ash Impacts List.

Ash is a particular problem for pasture and horticulture, covering crops and feed for animals. 

Disposal of ash in urban areas is essential to avoid blocked sewage or storm-water systems. Having capacity to store the large volumes of ash in landfills is also important for environmental reasons.

The Taupo eruption (also known as the Hatepe eruption) was the most recent major eruption of the Taupo Volcano about 1,800 years ago. It was the most violent eruption in the world in the last 5,000 years and was recorded by Chinese and Roman scholars.  It spread thick layers of ash over parts of the region – you can see layers of this ash on road cuttings on SH5 in particular.

Ashfalls from Ruapehu have affected the region in 1945, 1975, 1995 and 1996, and from Tongariro in 1896 and 2012. Peat bogs and swamps record a complex sequence of older ash layers from Taupo, Okataina, Ruapehu and Taranaki volcanoes dating back over 20,000 years. Lake bed core samples from Lake Tūtira have also shown debris from eruptions.

Eruptions from Ruapehu in 1995 and 1996 dispersed ash over much of the North Island, including Hawke’s Bay, closing the airport and creating a nuisance to other sectors.

An eruption from Tongariro in August 2012, resulted in a large cloud of fine ash being dispersed across Hawke’s Bay, particularly in the northwest. The ash closed Hawke’s Bay Airport. Homes, vehicles, roads and farms were dusted with a 1mm layer of fine grey ash from Wairoa to inland Napier, and there was a noticeable smell of sulphur. Hospitals reported no admissions due to respiratory problems, but pharmacies sold a lot of face masks.