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.


© Scoop Media

Business Headlines | Sci-Tech Headlines


Solid Energy: Plan To Shut Unprofitable Huntly East Mine

Solid Energy, the state-owned coal miner in voluntary administration, plans to shut down its unprofitable Huntly East mine and lay off 65 staff after deciding the site stands "no chance whatsoever" of finding a buyer. More>>


E Tū: Merger Creates NZ's Biggest Private Sector Union

E tū has been created by the merger of the Engineering, Printing and Manufacturing Union and Service and Food Workers’ Union. It represents more than 50,000 working New Zealanders in industries as diverse as aviation, construction, journalism, food manufacturing, mining and cleaning. More>>


Internet: NZ Govt Lifts Target Speeds For Rural Broadband

The government has lifted its expectations on faster broadband speeds for rural New Zealand as it targets increased spending on research and development in the country's information and communications technology sector, which it sees as a key driver for export growth. More>>


Banks: Westpac Keeps Core Government Transactions Contract

The local arm of Westpac Banking Corp has kept its contract with the New Zealand government to provide core transactions, but will have to share peripheral services with its rivals. More>>


Science Investment Plan: Universities Welcome Statement

Universities New Zealand has welcomed the National Statement of Science Investment released by the Government today... this is a critical document as it sets out the Government’s ten-year strategic direction that will guide future investment in New Zealand’s science system. More>>


Scouring: Cavalier Merger Would Extract 'Monopoly Rents' - Godfrey Hirst

A merger of Cavalier Wool Holdings and New Zealand Wool Services International's two wool scouring operations would create a monopoly, says carpet maker Godfrey Hirst. The Commerce Commission on Friday released its second draft determination on the merger, maintaining its view that the public benefits would outweigh the loss of competition. More>>


Get More From Scoop

Search Scoop  
Powered by Vodafone
NZ independent news