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

 


Gravity Survey Included In Christchurch Subsurface Study

MEDIA RELEASE from GNS Science 12 APRIL 2011

Gravity Survey Included In Christchurch Subsurface Study

GNS Science will spend the next two weeks undertaking a gravity survey of Christchurch and the Canterbury Plains to get a clearer picture of the subsurface structure of the region.

The project is part of a multi-pronged effort to learn more about the geological structure under Canterbury to help with earthquake recovery and rebuilding decisions in the wake of the devastating magnitude 6.3 earthquake on 22 February 2011.

Information collected during the gravity survey will be combined with seismic reflection data and aeromagnetic data to give scientists a clearer view of the subsurface and help locate any faults.

Several hundred gravity measurements already exist in Canterbury, some of them dating back several decades.

However, the spacing between the measurement points is uneven so the knowledge of the subsurface geology in some areas is good and quite poor in other areas.

Project leader, Vaughan Stagpoole of GNS Science, said the main aim of this initiative was to achieve more uniform coverage of gravity measurements and therefore more uniform information about subsurface geology.

“We hope to collect gravity data at up to 200 locations in Canterbury during the next two weeks,” Dr Stagpoole said.

The scientists will be using a highly sensitive gravity meter, which is about the size of a brief case. They place it on the ground at each location for a few minutes and record the measurement visually from the instrument.

“Typically we place the instrument beside a road or a farm track and it takes just a few minutes at each location to record the gravity,” Dr Stagpoole said.

Small changes in gravity measurements over a region help scientists determine geological structures in the subsurface. The instrument is sensitive to subtle changes in gravity that can be associated with the density of different rock types.

The measurement locations will cover the region where earthquake activity has occurred since September 2010, including some locations in the Port Hills.

The gravity data will augment information from a seismic survey of Christchurch currently being undertaken by the University of Canterbury and its Canadian associates. The seismic data will enable scientists to map faults that may be hidden under hundreds of meters of gravels and sediments.

A third leg of the research will involve an aerial survey of Christchurch to measure magnetic variations in the subsurface.

This is likely to involve a light aircraft flying on a grid pattern and carrying sophisticated magnetic measuring equipment.

The fourth and final leg of the project is detailed analysis of all the aftershocks. GNS Science has been undertaking this work since September 2010. The analysis helps scientists understand the size and orientation of the faults under Canterbury. The work is taking place under contract to the Canterbury Earthquake Recovery Authority and the Ministry of Civil Defence and Emergency Management. Both organisations will use the data, along with other information, to help with planning and rebuilding decisions.

END


© Scoop Media

 
 
 
 
 
Business Headlines | Sci-Tech Headlines

 

Pre-Budget: Computer Emergency Response Team, Assemble!

John Key told the country's first ever Cyber Security Summit in Auckland that the government had earmarked funding set up a national Computer Emergency Response Team to help prevent and act on cyber incidents in partnership with the private sector and other organisations. More>>

ALSO:

Job Cutter Goes: Mark Weldon To Step Down As MediaWorks CEO

“When I joined MediaWorks in August 2014, I had a mandate to lead a significant change programme to bring the business back from receivership into a position where it could once again be a strong competitor in the market, with a sound and sustainable future. It was a big brief, laden with inherent challenges, but I took it in good faith and have dedicated myself fully to the goal since." More>>

ALSO:

Must Sell 20 Petrol Stations: Z Cleared To Buy Caltex Assets

Z Energy is allowed to buy the Caltex and Challenge! petrol station chains but must sell 19 of its retail sites and one truck-stop, the Commerce Commission has ruled in a split decision that acknowledges possible retail price coordination between fuel retailers occurs in some regions. More>>

ALSO:

Huntly: Genesis Extends Life Of Coal-Fuelled Power Station To 2022

Genesis Energy will keep its two coal and gas-fired units at Huntly Power Station operating until 2022, having previously said they'd be closed by 2018, after wringing a high price from other electricity generators who wanted to keep them as back-up. More>>

ALSO:

Dammed If You Do: Ruataniwha Irrigation Scheme Hits Farmer Uptake Targets

Enough Hawke's Bay farmers have signed up for water from the proposed Ruataniwha Water Storage Scheme for it to go ahead as long as a cornerstone institutional capital investor can be found to back it, its regional council promoter announced. More>>

ALSO:

Reserve Bank: OCR Stays At 2.25%

Reserve Bank governor Graeme Wheeler kept the official cash rate at 2.25 percent, in a decision traders had said could go either way, while predicting inflation will pick up as the slump in oil prices washes out of the data and capacity pressures start to build in the economy. More>>

ALSO:

Get More From Scoop

 
 
 
 
 
 
 
 
 
Sci-Tech
Search Scoop  
 
 
Powered by Vodafone
NZ independent news