Water surge damages boats after 'doozy' of an earthquake under Lake Taupō
Thursday, 1 December 2022
An overnight surge of water from an earthquake in Taupō left a telltail line of debris and sunken pedal boats in its wake.
The 5.6 earthquake struck 15km south-west of the lakeside town at a depth of 5km. Aftershocks, measuring from M2.5 to M3.9, have followed the initial shake at 11.47pm Wednesday.
A series of waves on the lake – described as mini-tsunamis – wrecked two of Taupō Pedal Boats’ vessels, which was “not a great start” to their summer season.
Quake-induced wave clusters pulled the pedal boats off the beach and dashed them on the rocks at Wharewaka, near Four Mile Bay, said Jess Ratana, who owns the business with Kiripiti Bowden.
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“It was so bizarre. I’ve been living in Taupō all my life, and we have had lots of quakes before, but not like this,” Ratana said.
“We got a call at 6am saying some of our boats were up on the rocks and had been badly damaged.
“I was really surprised because we had pulled the boats further up the beach when that storm came through.
“You could see a line of debris about 12m up on the beach … out on the lake were all of our boats.”
Ratana said they were still open for business and their four water bikes and stand-up paddle boards were not damaged, but the two popular pedal boats were write-offs.
“Insurance will cover the boats, but not the loss of income, and we will have to import more boats from overseas. By the time they get here it will be too late for this year, it’s gutting.”
She said she and her partner were woken up by the initial big quake and had a restless night as the aftershocks rolled through.
“It was out of the ordinary, and it was a long night. I was lying there thinking I couldn’t hear anything being smashed in the house and was pretty happy about that.
“Then we got that call, and we are now down two boats, it’s not a great start to the season at all.”
Another video posted online showed shallow cracks running tens of metres along the grassy lake foreshore.
The strong earthquake in Taupō was a “doozy”, according to the mayor.
David Trewavas was shaken awake along with the rest of his family, including his 16-year-old daughter who was literally shaken out of bed.
“I haven’t felt one of these since I was a kid,” he said on Thursday morning.
It was initially rated at magnitude 5.4 but was uprated to magnitude 5.6.
Weak quakes were still being recorded on Thursday, according to GeoNet.
Trewavas said lights came on around the neighbourhood as people checked in on one another.
“It was a real rumble and a serious quake. There had been some pre-shakes in the last few days.”
He said he checked with his infrastructure team who looked at wastewater and fresh water but believes there’s been no damage, but a full assessment will be done on Thursday.
There has been a watchful eye on Lake Taupō this year with hundreds of small quakes recorded under the lake but Trewavas said that residents are aware they live near an active super volcano.
“We live in paradise, so we put up with it.”
He believed there was no serious damage, with things falling off shelves possibly the worst of it, but they will be assessing further during the day.
Thousands felt shake
“Taupō had a strong shake with several aftershocks this evening,” GeoNet wrote on Twitter overnight, adding that thousands of people had felt the moderate quake.
“Earthquakes are common for this area at [Volcano Alert Level 1].
A map on the GeoNet website showed there were 5440 reports of shaking and that the quake was felt as far north as Whangarei and as far south as Christchurch.
GNS seismic duty officer John Ristau said the increased number of earthquakes are similar to other periods of quake clusters recorded in 2008-2009 and 2019. However, last night’s earthquake was the largest in the current sequence.
“The Taupō caldera volcano lies under the lake, and this earthquake and its aftershocks are not an indicator that the volcano is waking up now or that an eruption is on the way. Taupō volcano is still active, although it hasn’t erupted for hundreds of years.”
He said that Taupō volcano is currently at activity level 1. The last earthquake with a similar magnitude was in September 2019 with a similar aftershock sequence.
People woken by the shaking shared their experiences on social media, with some from Napier, Palmerston North and other areas reporting feeling the quake and aftershocks.
One social media user wrote that the quake was the “biggest [they’ve] felt” in Taupō, adding that there had been “plenty of aftershocks”.
Another reported that they had heard rumbling continue for over an hour after the largest quake, and that their two-storey house had been rocking during the shake.
There were no immediate reports of damage from the incidents.
Taupō’s volcanic alert level (VAL) was raised to 1 in September.
A VAL of 1 means “minor volcanic unrest” is causing ongoing earthquakes and ground deformation at Taupō volcano, both under the lake and on land surrounding it.
“There has been an increase in earthquakes and deformation (ground movement) at Taupō since May 2022 indicating volcanic unrest is occurring,” duty volcanologist Steven Sherburn told Stuff in September.
There have been 17 previous episodes of unrest there over the past 150 years.
“Several of these were more severe than what we are currently observing at Taupō, Sherburn said.
The last eruption at Taupō volcano was around 232AD and the chance of an eruption at Taupō remains “very low in any one year”, Sherburn said.
“Earthquakes are being caused by magma movement deep in the volcano,” GeoNet wrote on its website.
“The magma and surrounding hydrothermal fluids are creating stress in the rocks around and/or above the magma chamber, causing them to break, which we can see as earthquakes.”