A Rotorua resident whose house began to shake in the middle of the night thought there must be an earthquake, but was astonished to find it was an active mud pool erupting near her property.

Genna Emery lives 25 metres from the geothermal pool which became active recently, spurting steam onto nearby houses and bubbling mud. The billowing steam and mud had even covered her car outside.

“In the mornings the steam is bad and coming through mine and the neighbours properties. The smell is bad as well some days. The shakes of the house are still the same day and night.”

Emery contacted the council at the end of August when the house started to shake and was told it should die down over coming weeks and months.

But she says the pool has got bigger since the recent activity and is impacting people who live near it.

”I would be worried if it gets bigger, I am just hoping mother nature doesn't surprise us. I refuse to hang out my washing due to the strong smell and having our clothes stink.”

The street, in the Whakarewarewa region of Rotorua is known for its active geothermal activity.

While Rotorua residents are used to living on a sulphurous underworld, there have been concerns that if mudpots suddenly erupt and expand near houses, intense activity could open the ground under the houses.

Susan Gedye used to live on the street in 2019 but told Stuff she had to evacuate due to the geothermal activity, and was concerned it was happening again.

“I had to leave in a hurry because it was changing into a hole, and I was worried it would open up the ground and swallow the whole house up. Even as I was putting things in the car I was dodging spurts of flying hot mud coming from the geyser. I’m surprised the house is still there – and that they put more houses there since then.”

Steam from the mudpool was reaching houses nearby. Photo: Stuff.

GNS volcanologist Brad Scott says that same pool that had opened in 2019 had suddenly reactivated again. He had visited the site, and it was being monitored.

“It suddenly reactivated on August 12 and has been since then, which is what is causing the overflow of steam and mud. It is normal for the mud to bubble and steam to shoot up when a geothermal pool is active, because of the pressure built up in the mudpot. It has not become intense enough to cause concern for the houses – though the activity in the ground can be felt which is what is causing the houses to feel like they are shaking.”

The mud pool might just cool down, but was unlikely to disappear completely he says. It was also possible it could further expand, but ongoing monitoring of the site would ensure the safety of nearby houses.

Rotorua Lakes Council spokesperson told Stuff in a statement that it was reminding people to avoid the area where possible.

“Council cordoned off the area around the mud pool three weeks ago and continue to monitor the area to ensure public safety. There have been no recent reports to council from residents about the activity that would currently be cause for additional concern. However, staff periodically check the ground heat and gas emissions at the site as a precaution. We remind everyone to avoid that area if possible.”

- Annemarie Quill/Stuff.