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

 


NZ - German 3D survey: seabed gas hydrate and methane system

NZ - German 3D survey reveals massive seabed gas hydrate and methane system

A joint New Zealand-German research team has discovered a huge network of frozen methane and methane gas in sediments and in the ocean near New Zealand’s east coast. The 16-strong team is using state-of-the-art 3D and 2D seismic and echosounder technology to map both forms of methane within the ocean and beneath the seafloor.

The area off the North Island’s east coast is known to have very large active landslides, up to 15km long and 100m thick, and the team set out to discover what is causing them to move.

What they discovered was direct evidence of widespread gas in the sediment and ocean, and indications of large areas of methane hydrate, ice-like frozen methane, below the seafloor.

The team has identified 99 gas flares in a 50 km2 area, venting from the seabed in columns up to 250 m high. This is believed to be the densest concentration of seafloor gas vents known in New Zealand. 3D seismic data show that landslides and faults allow the gas built up in the sediment to be released into the ocean.

This discovery reveals a hydrate and gas field very different from others known in New Zealand.

“Previously all gas venting sites have been in deeper water and associated with large earthquake faults” say NIWA marine geologist and voyage leader Dr Joshu Mountjoy.

“What we have found is high density methane flares in very shallow water, as well as gas building up beneath a large landslide and being released along the landslide margins”.

In a recently submitted scientific paper the team proposed that these landslides might be the seafloor equivalent of glaciers, but with frozen methane instead of water ice, or alternatively that pressurized gas is causing them to progressively move downslope. The results from this expedition indicate that both of these are possibilities and provide data to carefully test these hypotheses.

The expedition took the opportunity to deploy the German research institute GEOMAR’s high resolution 3D seismic equipment known as the P-Cable from NIWA’s research vessel Tangaroa.

“This equipment is the best available for imaging fluid systems within the seafloor,” says co-leader Professor Sebastian Krastel of the University of Kiel. “The sediment, rocks and fluids we have mapped here are perfectly suited to this equipment, and the area mapped is one of the biggest ever mapped with the P-Cable seismic system.”

The work forms part of a larger project focused on understanding the dynamic interaction of gas hydrates and slow moving active landslides. Dubbed SCHLIP (Submarine Clathrate Hydrate Landslide Imaging Project), ongoing investigations in the project over the next decade will including drilling into the landslides themselves in 2016.

This first part of the project, SCHLIP-3D, is a collaboration between NIWA, GNS Science and the University of Auckland from New Zealand, GEOMAR and the University of Kiel from Germany, Oregon State University from the USA, and the University of Malta.

“The initial findings are very important” says Dr Mountjoy. “Methane is a very effective greenhouse gas and seabed methane release has the potential to dramatically alter the earth’s climate. As ocean temperatures change the methane hydrate system has the potential to become unstable.”

“In terms of natural hazards, the occurrence of very large slow landslides, rather than catastrophic ones, has major implications for the tsunami generating potential of landslides globally as slow landslides are unlikely to cause tsunami.”

“This type of slow moving submarine landslide is essentially unknown around the world, but it is very likely that they do occur widely and are an important process shaping continental margins”.

The team set off from Wellington on 14 April and finished the voyage on 8 May. The work is funded from New Zealand by MBIE and Germany by DFG.

ENDS

© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Scoop Business: RBNZ Keeps OCR At 3.5%, Signals Slower Pace Of Future Hikes

Reserve Bank governor Graeme Wheeler kept the official cash rate at 3.5 percent and signalled he won’t be as aggressive with future rate hikes as previously thought as inflation remains tamer than expected. The kiwi dollar fell to a seven-month low. More>>

ALSO:

Weather: Dry Spells Take Hold In South Island

Many areas in the South Island are tracking towards record dry spells as relatively warm, dry weather that began in mid-August continues... for some South Island places, the current period of fine weather is quite rare. More>>

ALSO:

Scoop Business: Productivity Commission To Look At Housing Land Supply

The Productivity Commission is to expand on its housing affordability report with an investigation into improving land supply and development capacity, particularly in areas with strong population growth. More>>

ALSO:

Forestry: Man Charged After 2013 Death

Levin Police have arrested and charged a man with manslaughter in relation to the death of Lincoln Kidd who was killed during a tree felling operation on 19 December 2013. More>>

ALSO:

Smells Like Justice: Dairy Company Fined Over Odour

Dairy company fined over odour Dairy supply company Open Country Dairy Limited has been convicted and fined more than $35,000 for discharging objectionable odour from its Waharoa factory at the time of last year’s ”spring flush” when milk supply was high. More>>

Scoop Business: Dairy Product Prices Decline To Lowest Since July 2012

Dairy product prices dropped to the lowest level since July 2012 in the latest GlobalDairyTrade auction, led by a slump in rennet casein and butter milk powder. More>>

ALSO:

SOE Results: TVNZ Lifts Annual Profit 25% On Flat Ad Revenue, Quits Igloo

Television New Zealand, the state-owned broadcaster, lifted annual profit 25 percent, ahead of forecast and despite a dip in advertising revenue, while quitting its stake in the pay-TV Igloo joint venture with Sky Network Television. More>>

ALSO:

Get More From Scoop

 
 
Computer Power Plus

Standards New Zealand

Standards New Zealand
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news