For thousands of people across the central North Island, Saturday began with a jolt. A magnitude 5.9 earthquake struck near Taumarunui at 4.51am on 25 July, waking sleepers from the Waikato to Wellington and shaking buildings across a wide stretch of the country before dawn.
GeoNet, the agency that monitors earthquakes and volcanoes in New Zealand, placed the quake five kilometres south of Taumarunui at a depth of about nine kilometres. That shallow depth is the main reason so many people felt it so sharply. Energy from a quake close to the surface has less ground to pass through before it reaches homes and towns, so the shaking arrives harder and louder than a deeper quake of the same size would.
Near the epicentre the shaking reached what GeoNet classes as severe, the level at which people find it hard to stand, unsecured objects can be thrown from shelves and some older or weaker buildings can be damaged. A little further out the shaking eased to strong and then moderate, which is the pattern you would expect as the ground absorbs the energy with distance.
The public response was immediate. Within a couple of hours GeoNet had logged felt reports from more than 5,700 separate locations, with a small number of people close to the epicentre describing violent shaking at the very top of the intensity scale. RNZ reported that nearly 23,000 felt reports had been filed to GeoNet by 6am, one of the largest responses to a single earthquake in New Zealand this year.
The tremor was felt well beyond the King Country. People reported the shaking in Auckland to the north, across the Bay of Plenty and Hawke’s Bay, down through the lower North Island and as far south as the top of the South Island, according to RNZ. A quake being felt over such a large area does not mean it was dangerous everywhere. Most of those people felt a gentle roll or a short rattle rather than anything alarming, because the strong shaking stays close to the source while the weaker, longer waves travel much further.
GeoNet recorded a steady run of smaller quakes in the same area through the morning, the largest around magnitude 3.7, with at least eight aftershocks logged in the two hours after the main shock. Aftershocks are normal and expected after an earthquake of this size, as the ground around the fault settles back into place. They can carry on for days or weeks, usually getting smaller and less frequent over time, though a larger one is always possible and worth being ready for.
In the hours after the quake there were no reports of serious damage or injuries, and the shaking arrived at a time when most people were at home in bed rather than out on the roads or at work. Taumarunui itself is a small town of a few thousand people in the Ruapehu District, sitting where the Ongarue and Whanganui rivers meet in the middle of the North Island. It is well used to the ground moving. The central North Island is one of the more seismically active parts of the country, wrapped around the volcanic zone that runs from Ruapehu and Tongariro up to White Island and beyond.
Despite that volcanic setting, a quake like this one is tectonic rather than volcanic. It comes from the slow grind of the Earth’s crust breaking and slipping along a fault, the same process that produces most earthquakes in New Zealand, and it is not a sign that any nearby volcano is stirring. Because the epicentre was well inland, there was no tsunami risk from the shake.
The standard advice during any strong earthquake is to drop, cover and hold. Get down low, take cover under a sturdy table or against an interior wall, and hold on until the shaking stops. If you are in bed, the safest thing is usually to stay there and protect your head and neck with a pillow rather than trying to move through a dark, shaking house. Once the ground is still it is worth checking on neighbours, especially older people living alone, and keeping an eye out for slower hazards such as cracked chimneys, broken glass or spilled chemicals.
A morning like this is also a useful nudge to check that the basics are in place. A stocked emergency kit, a stored supply of water, a torch within reach and a plan for how a household would get in touch if a bigger quake struck during the day rather than before dawn all make a real difference. Emergency managers have long said that the best time to prepare is on an ordinary quiet day, not in the minutes after the ground has already started to move.
You can see the latest quakes as they are recorded, along with where they struck and how hard they shook, on our live New Zealand earthquake map.
Did you feel the Taumarunui earthquake, and where were you when it hit? Share your experience in the comments below.
This article was written by AI, briefed to report the facts, hopefully without some of the bias people bring to the job 🙂
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