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Frequently asked questions 

What is a deep seismic reflection survey?

A deep seismic reflection survey is a low-impact data collection technique that enables geoscientists to interpret geological features up to 50 kilometres beneath the earth’s surface.  

To conduct a survey, seismic waves are sent deep into the earth from Vibroseis trucks. The process is similar to using sound waves for an ultrasound. The Vibroseis trucks travel slowly across the landscape approximately 8 to 10 kilometres per day, stopping at frequent intervals to send down seismic waves from vibrators mounted on the trucks.

The seismic waves are reflected (echoed) off rock formations deep within the earth. The echoes are recorded by sensitive microphones on the surface called geophones that are spread out over a distance of up to twelve kilometres. The signals are recorded in specialised data recorders and processed to produce an image of the subsurface. This enables geoscientists to gather data to build knowledge of the underlying geology.

Why is this survey being carried out?

The survey is part of a greater collaborative scientific research project across southeast Australia in Victoria and New South Wales: the Southeast Lachlan Crustal Scale Transect. Project partners are Geological Survey of Victoria, Geoscience Australia, the Geological Survey of New South Wales and AuScope Limited. 

The focus of the survey is geology; the rock types, faults and their distribution. The area to be surveyed is not prospective for oil and gas. The survey is low impact and will not affect the environment or physical infrastructure.

The data collected helps geoscientists, governments and land resource managers to learn about the geology and structure of the Earth’s crust. The results will help build a geological picture that can be used to understand the evolution of the landscape, including rocks, soil, groundwater and other earth resources. The states inland geology is the foundation for building roads, dam walls and most other infrastructure. Gaining a deeper understanding of the geology will allow for better informed and safer land management.

When is the survey being carried out?

The survey will be carried out between February and June 2018.

Where is this survey being carried out?

The survey will travel mostly across along local roads, a small number of private properties, Crown land, through national parks. The survey will be conducted in two lines:

Line 1 - Starting south of Benalla and travelling approximately 280 kilometres eastwards towards Tom Groggin and into New South Wales.

Line 2 - Starting north of Benambra and travelling approximately 180 kilometres south eastwards near Bendoc and into New South Wales

Towns the survey will travel through are Molyullah, Edi, Merriang, Rosewhite, Kancoona, Eskdale, Upper Gundowring, Runny Creek, Ovens, Myrtleford, Benambra, Wulgulmerang, Wulgulmerang East, Deddick Valley and Bendoc.

The survey will also travel through the Alpine, Mt Buffalo, Snowy River and Errinundra national parks

Who is carrying out this survey?

The survey has been commissioned by the Geological Survey of Victoria in partnership with Geoscience Australia, Geological Survey of New South Wales and AuScope Limited. It is being carried out by specialist contractors with extensive experience of carrying out seismic surveys.

Will this survey have an impact on my land?

The surveys will be conducted from trucks with specialised seismic equipment. These trucks travel slowly across the landscape, frequently stopping at pre-determined points to send down seismic waves (similar to sound waves) by vibrators mounted on the vehicles. They are of low intensity and cause no damage to infrastructure or the environment. The noise generated by the hydraulic vibrators is similar to an idling road train. 

The trucks are pre-programmed so that vibrations are only generated at the pre-determined points. The vibrations are generated clear of buildings and significant infrastructure. Vibrations that could potentially damage infrastructure would also damage the survey equipment and generate unwanted ‘noise’ in the data. In this situation the Vibroseis trucks will automatically shut down.

While the survey will have no impact on the land, access to a small number of private properties and other land may require fences and other infrastructure to be removed temporarily to allow the trucks to travel in as straight a line as possible alone the survey route. The fences removed will be replaced and any land temporarily impacted rehabilitated following the work. Arrangements will be made with the property owner and/or land manager prior to the survey. 

Who authorised the survey?

Under Victorian laws, surveyors engaged by the Geological Survey of Victoria have been given the right to carry out this research. This seismic survey is authorised under Section 112 (1) of the Mineral Resources (Sustainable Development) Act 1990.

The seismic survey work is overseen by the Department of Economic Development, Jobs, Transport and Resources. A range of other Victorian government authorities have also been consulted, such as Parks Victoria, the Department of Environment, Land, Water and Planning, VicRoads and local councils. 

Are there any risks?

A detailed risk assessment has been prepared to ensure the safety of the survey team, stakeholders, local infrastructure and the environment. Procedures will be implemented to avoid transport of soil and plant material where required.

Is there drilling involved?

No.Three Vibroseis trucks drive slowly in convoy along the survey route, stopping at frequent intervals to generate the seismic signal by synchronously vibrating the ground beneath them for 10 to 15 seconds. The vibrations are about the same as those generated by a large truck driving past. 

Three trucks are required to generate sufficient seismic energy to see deep into the earth. The trucks are pre-programmed so that vibrations are only generated at the pre-determined points. The vibrations are generated clear of buildings and significant infrastructure.

The highly sensitive geophones are embedded in the surface to a depth of approximately 100-150mm to minimise the detection of noise on the surface when listening for the echoes from great depth.

How were the survey areas selected?

The survey sites have been chosen by scientists where more data is needed to understand the region’s geology and how it has evolved over time. The survey lines have been designed across the region to be as straight as possible to achieve the best scientific result.  

What will the results be used for?

The data will be incorporated into the existing state and national seismic databases. It will be used by the Geological Survey of Victoria to help build a publicly available, digital three-dimensional (3D) geological model to increase understanding of the region’s geology and to present this information visually. The new data will complement existing data from previous surveys in the region and help build an understanding of how eastern Victoria has evolved over time.

Have surveys like this been carried out elsewhere in Victoria?

Yes. The Geological Survey has safely carried out deep seismic reflection surveys using the same techniques across all of Victoria, including central and western Victoria in 2006 and 2009 respectively, to help build up an understanding of how the geology of Victoria has evolved over time.

Is this survey looking for minerals?

This survey is being conducted to improve scientists’ understanding of the geology of the region and of how it has evolved over time. The technique cannot directly detect minerals. Minerals are known in the region and the results of the survey may potentially provide context for how these minerals have formed over time. 

Is this related to onshore gas or fracking?

No. This survey is being carried out to better understand the geology of eastern Victoria (and southeast Australia) and how it has evolved over time. The area to be surveyed is not prospective for oil and gas. The survey has nothing to do with fracking.

When will the results of this survey be available?

It is anticipated that the results of this survey will be available in 2019.

Where will I be able to access the results of this survey?

The results of this survey will be publically available through Geoscience Australia’s website and through the Geological Survey of Victoria.

Can I get more information?

Yes. Send an email with specific questions to evgi.info@ecodev.vic.gov.au and your query will be passed along to the appropriate staff member for answering.