NZ Herald
  • Home
  • Latest news
  • Herald NOW
  • Video
  • New Zealand
  • Sport
  • World
  • Business
  • Entertainment
  • Podcasts
  • Quizzes
  • Opinion
  • Lifestyle
  • Travel
  • Viva
  • Weather

Subscriptions

  • Herald Premium
  • Viva Premium
  • The Listener
  • BusinessDesk

Sections

  • Latest news
  • New Zealand
    • All New Zealand
    • Crime
    • Politics
    • Education
    • Open Justice
    • Scam Update
  • Herald NOW
  • On The Up
  • World
    • All World
    • Australia
    • Asia
    • UK
    • United States
    • Middle East
    • Europe
    • Pacific
  • Business
    • All Business
    • MarketsSharesCurrencyCommoditiesStock TakesCrypto
    • Markets with Madison
    • Media Insider
    • Business analysis
    • Personal financeKiwiSaverInterest ratesTaxInvestment
    • EconomyInflationGDPOfficial cash rateEmployment
    • Small business
    • Business reportsMood of the BoardroomProject AucklandSustainable business and financeCapital markets reportAgribusiness reportInfrastructure reportDynamic business
    • Deloitte Top 200 Awards
    • CompaniesAged CareAgribusinessAirlinesBanking and financeConstructionEnergyFreight and logisticsHealthcareManufacturingMedia and MarketingRetailTelecommunicationsTourism
  • Opinion
    • All Opinion
    • Analysis
    • Editorials
    • Business analysis
    • Premium opinion
    • Letters to the editor
  • Politics
  • Sport
    • All Sport
    • OlympicsParalympics
    • RugbySuper RugbyNPCAll BlacksBlack FernsRugby sevensSchool rugby
    • CricketBlack CapsWhite Ferns
    • Racing
    • NetballSilver Ferns
    • LeagueWarriorsNRL
    • FootballWellington PhoenixAuckland FCAll WhitesFootball FernsEnglish Premier League
    • GolfNZ Open
    • MotorsportFormula 1
    • Boxing
    • UFC
    • BasketballNBABreakersTall BlacksTall Ferns
    • Tennis
    • Cycling
    • Athletics
    • SailingAmerica's CupSailGP
    • Rowing
  • Lifestyle
    • All Lifestyle
    • Viva - Food, fashion & beauty
    • Society Insider
    • Royals
    • Sex & relationships
    • Food & drinkRecipesRecipe collectionsRestaurant reviewsRestaurant bookings
    • Health & wellbeing
    • Fashion & beauty
    • Pets & animals
    • The Selection - Shop the trendsShop fashionShop beautyShop entertainmentShop giftsShop home & living
    • Milford's Investing Place
  • Entertainment
    • All Entertainment
    • TV
    • MoviesMovie reviews
    • MusicMusic reviews
    • BooksBook reviews
    • Culture
    • ReviewsBook reviewsMovie reviewsMusic reviewsRestaurant reviews
  • Travel
    • All Travel
    • News
    • New ZealandNorthlandAucklandWellingtonCanterburyOtago / QueenstownNelson-TasmanBest NZ beaches
    • International travelAustraliaPacific IslandsEuropeUKUSAAfricaAsia
    • Rail holidays
    • Cruise holidays
    • Ski holidays
    • Luxury travel
    • Adventure travel
  • Kāhu Māori news
  • Environment
    • All Environment
    • Our Green Future
  • Talanoa Pacific news
  • Property
    • All Property
    • Property Insider
    • Interest rates tracker
    • Residential property listings
    • Commercial property listings
  • Health
  • Technology
    • All Technology
    • AI
    • Social media
  • Rural
    • All Rural
    • Dairy farming
    • Sheep & beef farming
    • Horticulture
    • Animal health
    • Rural business
    • Rural life
    • Rural technology
    • Opinion
    • Audio & podcasts
  • Weather forecasts
    • All Weather forecasts
    • Kaitaia
    • Whangārei
    • Dargaville
    • Auckland
    • Thames
    • Tauranga
    • Hamilton
    • Whakatāne
    • Rotorua
    • Tokoroa
    • Te Kuiti
    • Taumaranui
    • Taupō
    • Gisborne
    • New Plymouth
    • Napier
    • Hastings
    • Dannevirke
    • Whanganui
    • Palmerston North
    • Levin
    • Paraparaumu
    • Masterton
    • Wellington
    • Motueka
    • Nelson
    • Blenheim
    • Westport
    • Reefton
    • Kaikōura
    • Greymouth
    • Hokitika
    • Christchurch
    • Ashburton
    • Timaru
    • Wānaka
    • Oamaru
    • Queenstown
    • Dunedin
    • Gore
    • Invercargill
  • Meet the journalists
  • Promotions & competitions
  • OneRoof property listings
  • Driven car news

Puzzles & Quizzes

  • Puzzles
    • All Puzzles
    • Sudoku
    • Code Cracker
    • Crosswords
    • Cryptic crossword
    • Wordsearch
  • Quizzes
    • All Quizzes
    • Morning quiz
    • Afternoon quiz
    • Sports quiz

Regions

  • Northland
    • All Northland
    • Far North
    • Kaitaia
    • Kerikeri
    • Kaikohe
    • Bay of Islands
    • Whangarei
    • Dargaville
    • Kaipara
    • Mangawhai
  • Auckland
  • Waikato
    • All Waikato
    • Hamilton
    • Coromandel & Hauraki
    • Matamata & Piako
    • Cambridge
    • Te Awamutu
    • Tokoroa & South Waikato
    • Taupō & Tūrangi
  • Bay of Plenty
    • All Bay of Plenty
    • Katikati
    • Tauranga
    • Mount Maunganui
    • Pāpāmoa
    • Te Puke
    • Whakatāne
  • Rotorua
  • Hawke's Bay
    • All Hawke's Bay
    • Napier
    • Hastings
    • Havelock North
    • Central Hawke's Bay
    • Wairoa
  • Taranaki
    • All Taranaki
    • Stratford
    • New Plymouth
    • Hāwera
  • Manawatū - Whanganui
    • All Manawatū - Whanganui
    • Whanganui
    • Palmerston North
    • Manawatū
    • Tararua
    • Horowhenua
  • Wellington
    • All Wellington
    • Kapiti
    • Wairarapa
    • Upper Hutt
    • Lower Hutt
  • Nelson & Tasman
    • All Nelson & Tasman
    • Motueka
    • Nelson
    • Tasman
  • Marlborough
  • West Coast
  • Canterbury
    • All Canterbury
    • Kaikōura
    • Christchurch
    • Ashburton
    • Timaru
  • Otago
    • All Otago
    • Oamaru
    • Dunedin
    • Balclutha
    • Alexandra
    • Queenstown
    • Wanaka
  • Southland
    • All Southland
    • Invercargill
    • Gore
    • Stewart Island
  • Gisborne

Media

  • Video
    • All Video
    • NZ news video
    • Herald NOW
    • Business news video
    • Politics news video
    • Sport video
    • World news video
    • Lifestyle video
    • Entertainment video
    • Travel video
    • Markets with Madison
    • Kea Kids news
  • Podcasts
    • All Podcasts
    • The Front Page
    • On the Tiles
    • Ask me Anything
    • The Little Things
  • Cartoons
  • Photo galleries
  • Today's Paper - E-editions
  • Photo sales
  • Classifieds

NZME Network

  • Advertise with NZME
  • OneRoof
  • Driven Car Guide
  • BusinessDesk
  • Newstalk ZB
  • Sunlive
  • ZM
  • The Hits
  • Coast
  • Radio Hauraki
  • The Alternative Commentary Collective
  • Gold
  • Flava
  • iHeart Radio
  • Hokonui
  • Radio Wanaka
  • iHeartCountry New Zealand
  • Restaurant Hub
  • NZME Events

SubscribeSign In
Advertisement
Advertise with NZME.
Home / New Zealand

Lahar larger but lacked the force of '53

By Simon O'Rourke
22 Mar, 2007 05:00 PM4 mins to read

Subscribe to listen

Access to Herald Premium articles require a Premium subscription. Subscribe now to listen.
Already a subscriber?  Sign in here

Listening to articles is free for open-access content—explore other articles or learn more about text-to-speech.
‌
Save

    Share this article

Left: The 5.2m high flood gauge in Whangaehu valley upstream of Tangiwai and right: 25 minutes later

Left: The 5.2m high flood gauge in Whangaehu valley upstream of Tangiwai and right: 25 minutes later

KEY POINTS:

Scientists say the Mt Ruapehu lahar was larger than the 1953 debris flow that caused the Tangiwai disaster.

But last Sunday's lahar lacked the violent force of the December 24, 1953, surge that wiped out the rail bridge at Tangiwai and led to the train plunge that cost
151 lives.

That was because of the comparative lack of debris it picked up on its way down the Whangaehu Valley last Sunday, said Dr Vern Manville of GNS Science.

"Our initial interpretation is that the 95-96 eruption did a good job of scouring out loose material from the gorge, whereas prior to the 1953 event there had been 30 years of no lahars and there was a much bigger accumulation of debris in the channel."

The lahar travelled at different speeds throughout its descent, the fastest of which was 60km/h, reached between the Crater Lake and the Whangaehu alpine hut. Those points were 2.5km from each other, Dr Manville said.

Another 2km separated the alpine hut from the Tukino skifield, where other measuring instruments indicated the lahar was travelling about 30km/h.

Further down, the debris flow slowed to 20km/h.

"They're back-of-the-envelope calculations," Dr Manville said.

History indicated the flow would have been running at 15km/h by the time it reached Tangiwai, but it was too early to accurately say what the speed was last Sunday.

"There is the average speed and there are local speeds, depending on the depth and flow. The more water, the more diluted it is [which applied to Sunday's event] and the slower it will go," he said.

"A build-up of sediment means it is more concentrated and it will go faster with all the energy that builds. It puts all its energy in to rushing along rather than splashing around."

According to Department of Conservation instruments, the "trip wire" indicated the lahar began at 11.22am. It reached the Tangiwai road bridge, 39.4km away, at 1.30pm.

Researchers from GNS Science and Massey University have spent the week gathering data from the lahar site as part of a $1 million research programme.

Dr Manville said this would ensure maximum scientific value from the event.

The money had come from a combination of the Marsden Fund ($700,000, administered by the Royal Society of New Zealand), the Earthquake Commission and the Foundation for Research, Science and Technology.

A plethora of digital information was captured by instruments installed along the Whangaehu Valley in advance of the tephra dam's gradual demise, Dr Manville said.

It would take months to sift through and interpret the data, but researchers were excited because this time around 10 times the amount of information was available.

"In 1995 there was just one measuring swipe taken on the whole river. This [current] data will be very valuable as it will mean the lahar will be extremely well characterised."

This meant the country would be in a better position to predict and plan for lahars, as well as determining how they might behave.

"All our years of effort have paid off. We have collected a world-class dataset that will make this the best-studied lahar ever."

Teams from Massey University and GNS Science have been on the mountain all week surveying deposits and taking samples for analysis. They have been joined by scientific groups from Hawaii, Japan, France and Britain.

The material collected will be studied in combination with photographs and television and video footage of the event.

A laser scan survey of the dam-breach site is planned over the next few days.

Lahar numbers

* Maximum speed as it tore down Whangaehu Valley high on the mountain: 60km/h

* Time from its start to Tangiwai road bridge, 39.4km away: 128 minutes

Advertisement
Advertise with NZME.
Advertisement
Advertise with NZME.
Save

    Share this article

Latest from New Zealand

New Zealand

Home detention for husband who helped public servant wife defraud Oranga Tamariki of $2m

19 Jun 12:44 AM
New Zealand

Man dies after hit-and-run; police release new images of suspect

19 Jun 12:37 AM
New Zealand

Coldest morning of the year hits Hawke's Bay, just in time for Matariki

19 Jun 12:19 AM

Jono and Ben brew up a tea-fuelled adventure in Sri Lanka

sponsored
Advertisement
Advertise with NZME.

Latest from New Zealand

Premium
Audrey Young: Cooks crisis complicates Luxon's big meeting with President Xi

Audrey Young: Cooks crisis complicates Luxon's big meeting with President Xi

19 Jun 12:49 AM

OPINION: The timing of Winston Peters' announcement is curious.

Home detention for husband who helped public servant wife defraud Oranga Tamariki of $2m

Home detention for husband who helped public servant wife defraud Oranga Tamariki of $2m

19 Jun 12:44 AM
Man dies after hit-and-run; police release new images of suspect

Man dies after hit-and-run; police release new images of suspect

19 Jun 12:37 AM
Coldest morning of the year hits Hawke's Bay, just in time for Matariki

Coldest morning of the year hits Hawke's Bay, just in time for Matariki

19 Jun 12:19 AM
Help for those helping hardest-hit
sponsored

Help for those helping hardest-hit

NZ Herald
  • About NZ Herald
  • Meet the journalists
  • Newsletters
  • Classifieds
  • Help & support
  • Contact us
  • House rules
  • Privacy Policy
  • Terms of use
  • Competition terms & conditions
  • Our use of AI
Subscriber Services
  • NZ Herald e-editions
  • Daily puzzles & quizzes
  • Manage your digital subscription
  • Manage your print subscription
  • Subscribe to the NZ Herald newspaper
  • Subscribe to Herald Premium
  • Gift a subscription
  • Subscriber FAQs
  • Subscription terms & conditions
  • Promotions and subscriber benefits
NZME Network
  • The New Zealand Herald
  • The Northland Age
  • The Northern Advocate
  • Waikato Herald
  • Bay of Plenty Times
  • Rotorua Daily Post
  • Hawke's Bay Today
  • Whanganui Chronicle
  • Viva
  • NZ Listener
  • Newstalk ZB
  • BusinessDesk
  • OneRoof
  • Driven Car Guide
  • iHeart Radio
  • Restaurant Hub
NZME
  • About NZME
  • NZME careers
  • Advertise with NZME
  • Digital self-service advertising
  • Book your classified ad
  • Photo sales
  • NZME Events
  • © Copyright 2025 NZME Publishing Limited
TOP
search by queryly Advanced Search