Video | Business Headlines | Internet | Science | Scientific Ethics | Technology | Search


Scientists probe Lake Rotomahana's volcanic heat engine

6 March 2014

Scientists probe Lake Rotomahana's volcanic heat engine

The scientists who found remnants of the Pink and White Terraces under Lake Rotomahana two years ago are back at the lake this week measuring its geothermal heat output.

For many years scientists have known there is a large active geothermal system under the lake, and this will be the most sophisticated attempt at measuring the heat output of the 800 hectare lake.

To achieve this they are using state-of-the-art heat measuring devices that are being used in New Zealand for the first time. The instruments sit on the lakebed for up to 24 hours collecting heat measurements before being moved to a new spot.

They are also using a camera to take high-resolution photos of geothermal features on the lake floor and are collecting water samples from the lake floor for analysis.

The project is being led by GNS Science in collaboration with Woods Hole Oceanographic Institution and the National Oceanic and Atmospheric Administration - both from the US - and the University of Waikato. The project also has the support of the Te Arawa Lakes Trust.

The scientists are measuring heat being produced at 110 grid points on the floor of the lake to calculate the heat being produced by the entire lake. This is only the third time the US-developed heat-measuring devices have been used, and the first time they have been deployed in a lake.

Preliminary results from the first batch of measurements have shown a couple of hot spots where heat energy output (watts per square metre) is about five times higher than similar measurements at hot vents on the seafloor of the Pacific.

Results for the entire lake will represent another piece in the puzzle to help scientists understand the size and the state of the magma body that underlies this part of the Bay of Plenty.

"Once we have the information about the lake's heat energy output, we will be able to put together a comprehensive story on the evolution of the volcano-geothermal system since the Tarawera eruption of 1886," said project leader Cornel de Ronde of GNS Science.

"The initial results show the amount of heat passing through the lake floor is truly impressive. There's about two square kilometres of the lake floor where there is enough heat energy to power a 60 watt lightbulb every square metre," Dr de Ronde said.

Te Arawa Lakes Trust Chief Executive Roku Mihinui said the survey had given a clearer picture of what the Tarawera eruption did to Lake Rotomahana and the surrounding landscape where some of the Trust's ancestors had lived.

"It has also given some inkling of the latent power of the geothermal activity under the lake, as well as potential development opportunities and possible risks."

The were was still more to learn and the Trust hoped that the New Zealand and American scientists would continue their research, Mr Mihinui said.

Lake Rotomahana is the warmest of the Rotorua lakes and sits at about 11 to 14 degrees Celsius throughout the year.

The Okataina Volcanic Centre gives rise to a substantial amount of volcanic and geothermal activity east of Rotorua, and was the source of the eruption of Mount Tarawera in June 1886.

The Okataina Volcanic Centre lies east of Rotorua and formed between 250,000 and 50,000 years ago. It has erupted six times in the past 10,000 years, most recently with the eruption of Mount Tarawera in 1886. The time between eruptions from this Centre is long, between 700 and 3000 years. Eruptions from this type of volcanic centre are usually many times larger than those from cone volcanoes such as Ruapehu, Ngauruhoe, and Tongariro.


© Scoop Media

Business Headlines | Sci-Tech Headlines


Trade: NZ Trade Deficit Widens To A Record In September

Oct. 27 (BusinessDesk) - New Zealand's monthly trade deficit widened to a record in September as meat exports dropped to their lowest level in more than three years. More>>


Animal Welfare: Cruel Practices Condemned By DairyNZ Chief

DairyNZ chief executive Tim Mackle says cruel and illegal practices are not in any way condoned or accepted by the industry as part of dairy farming.

Tim says the video released today by Farmwatch shows some footage of transport companies and their workers, as well as some unacceptable behaviour by farmers of dragging calves. More>>


Postnatal Depression: 'The Thief That Steals Motherhood' - Alison McCulloch

Post-natal depression is a sly and cruel illness, described by one expert as ‘the thief that steals motherhood’, it creeps up on its victims, hiding behind the stress and exhaustion of being a new parent, catching many women unaware and unprepared. More>>


DIY: Kiwi Ingenuity And Masking Tape Saves Chick

Kiwi ingenuity and masking tape has saved a Kiwi chick after its egg was badly damaged endangering the chick's life. The egg was delivered to Kiwi Encounter at Rainbow Springs in Rotorua 14 days ago by a DOC worker with a large hole in its shell and against all odds has just successfully hatched. More>>


International Trade: Key To Lead Mission To India; ASEAN FTA Review Announced

Prime Minister John Key will lead a trade delegation to India next week, saying the pursuit of a free trade agreement with the protectionist giant is "the primary reason we're going" but playing down the likelihood of early progress. More>>



MYOB: Digital Signatures Go Live

From today, Inland Revenue will begin accepting “digital signatures”, saving businesses and their accountants a huge amount of administration time and further reducing the need for pen and paper in the workplace. More>>

Oil Searches: Norway's Statoil Quits Reinga Basin

Statoil, the Norwegian state-owned oil company, has given up oil and gas exploration in Northland's Reinga Basin, saying the probably of a find was 'too low'. More>>


Modern Living: Auckland Development Blowouts Reminiscent Of Run Up To GFC

The collapse of property developments in Auckland is "almost groundhog day" to the run-up of the global financial crisis in 2007/2008 as banks refuse to fund projects due to blowouts in construction and labour costs, says John Kensington, the author of KPMG's Financial Institutions Performance Survey. More>>


Get More From Scoop

Search Scoop  
Powered by Vodafone
NZ independent news