Road closed after Mauao slip at site of deadly landslide

A temporary road closure is in place following slips on Mauao.

Tauranga City Council said that Adams Ave, between Pilot Bay and the Maunganui Rd roundabout, would be temporarily closed to vehicles, effective immediately.

It said the closure was a precautionary measure to ensure public safety while the area was at higher risk of further movement.

The council said the slip was a “major regression” that happened at the site of a landslide that took place on January 22 at the Mount Maunganui Beachside Holiday Park.

“The regression extends approximately 20m with a run out of approximately 100m,” the council said in a statement.

“While it has not extended as far as the original run out, the material is saturated, mobile and fluid.”

This raised the Trigger Action Response Plan alert level to level three and led to the closure of Adams Ave, the council said.

It could not confirm if the closure would be lifted on Monday but said geotechnical assessments were still happening and updates would be provided when there was more information to share.

Pedestrians could still use the southern Adams Ave footpath but the council has asked for people to not linger, and to follow directions from staff on site.

Two Māori Wardens at the scene said there had been two fresh slips. One slip was at the original slip site above the camping ground and hot pools that took the lives of six people earlier this year.

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It was unclear where the second slip was located.

News of the slips came after an earthquake struck south of Taumarunui in the Manawatū-Whanganui region yesterday, with tens of thousands of people reporting feeling the shake.

Tauranga City Council said Adams Ave, between Pilot Bay and the Maunganui Rd roundabout, would be temporarily closed to vehicles, effective immediately. Photo / Rosalie Liddle Crawford

The quake hit 5km south of Taumarunui at 4.51am, at a depth of 9km.

GeoNet said the quake had been felt across most of the North Island.

Minor slips were reported on roads in the region and drivers were urged to drive with caution.

GeoNet said the earthquake was due to “normal faulting” in the upper crust of the Australian Plate, which is a lengthening, or extension, of a portion of Earth’s crust.

“This area is at the edge of the Taupō Volcanic Zone, where the crust is stretching thinner due to the subduction of the Pacific Plate below and associated processes.”

GeoNet said this meant normal faulting in this area was typical.

“We also see large earthquakes at depth in this area, like the M6.2 that occurred in 2018 deep in the subducting Pacific Plate, which is plunging into the earth some 100 km beneath the area.”

Meanwhile, a small “eruption” was spotted at a Rotorua golf course following the earthquake.

GeoNet said it was difficult to “conclusively link” minor changes in surface features to any external influences, especially earthquake shaking from a distant event.

The spokesperson said there may be many factors that align to cause minor changes in a geothermal system.

“We can’t rule it out,” the duty volcanologist said.

GeoNet said the video showed a “small-scale geysering” within one of the larger pools in the Arikikapakapa area.

The Arikikapakapa area is characterised by steam-heated surface geothermal features, so enhanced activity was not unusual.

“This area lies within the Rotorua Geothermal Field where there are many geothermal surface features such as mud pools, hot springs, geysers and hot and steaming ground.”

Michael Marston told the Herald he was roughly halfway through a round of golf with mates when he heard gunshot-type noises.

“We heard a whole lot of shotgun sounds like duck hunting or something, it happened quite quickly, then yeah saw all this smoke and knew it was an eruption.”

He said he was about 600m from the eruption and “wasn’t keen to hang around”.

“I’m quite new to the area I’ve been here seven years, and I didn’t want to hang around and find out [how big it would get].”

Marston said while eruptions weren’t uncommon in the area, it was the biggest he had personally seen.

“People have told me there have been bigger ones on lakes in the area. Everyone else stayed to finish the game.”

He said the phenomenon, which “shows the unpredictable nature of the environment”, lasted several minutes.

Dr Finnigan Illsley-Kemp, Victoria University of Wellington research fellow in the School of Geography, Environment and Earth Sciences, told the Herald there could have been a link between the two events.

He said it was hard to tell exactly if they were connected or not because a “small hydrothermal eruption” in Rotorua was relatively common and could have been a coincidence.

“It is feasible that they could be connected.”

Illsley-Kemp said it was reasonable to draw a link between shaking from a large earthquake and shallow geothermal systems becoming destabilised.

“There’s no particular evidence that you get an increase in volcanic activity after earthquakes of this size. For very large earthquakes, there is maybe some evidence that you might get a link,” he said.