Frequently asked questions

What is Tellus South West?

Tellus South West is a survey project that will map the soils and rocks of the majority of the south west region of England, covering most of Cornwall, Devon and part of Somerset, using modern scientific equipment mounted on a light aircraft flying low over the landscape. Survey work will be carried out in summer and autumn 2013.

Why do we need to do this survey?

The survey will give a comprehensive, three-dimensional picture of the underground environment in the region, to depths of many hundreds of metres, that will help us manage natural resources and the environment in the future. The data will be compiled into maps that will be made freely available online. This information will be of great use to policy makers, researchers, students and industry for many decades to come.

Where does the name ‘Tellus’ come from?

Tellus was the Roman goddess of the Earth. Tellus will measure the properties of three key elements of the earth — soil, rock and water — and help us understand how the subsurface environment is being changed by the activities of humans.

Tellus surveys have previously been carried out in Northern Ireland in 2007 and in the Republic of Ireland in 2011 and are routinely flown all over the world.

Pioneering surveys of this type were first flown in Britain in the 1950s, but data collected by these older surveys are crude by modern standards.

What kind of aircraft was used in the survey?

The aircraft was a Reims Cessna F406 operated by the specialist survey company, Fugro Airborne Surveys of South Africa. The plane was white, with twin turboprop engines, and bears the registration number ZS-SSC.

Fugro operates a fleet of similarly equipped aircraft that carry out airborne surveys in many countries worldwide. The aircraft will be a familiar sight over the region for local residents and visitors over the summer and autumn 2013.

What height and speed did the survey aircraft fly?

The aircraft flew at a safe height authorised by the Civil Aviation Authority. Over rural areas this was 80 m — about eight times the height of a two storey house. Over urban areas the height was 240 m.

The speed of the aircraft was about 130 mph. The sound of the aircraft passing overhead is similar to that of a passing lorry.

Why does it have to fly at a low altitude?

The plane flew back and forth over the region in parallel, north–south lines spaced 200 metres apart, turning over the sea. It flew at a low altitude to allow the sensitive instruments on board the plane to measure the properties of soil and rocks more accurately.

What equipment did the plane carry and what did it measure?

The aircraft carried a range of instruments for navigation and for measuring geophysical properties of the ground.

The navigation instruments carried on the aircraft included:

  • a satellite navigation system
  • a radar altimeter for measuring altitude
  • a video camera, which gives us a record of where the plane has flown. The video footage will not be used for any other purpose.

The geophysical instruments on board the plane were:

  • a magnetometer, which measures minute variations in the Earth’s magnetic field
  • a gamma ray detector, which measures the very low levels of natural background radioactivity present in all soils and rocks

The only signals emitted from the aircraft were for flight communications equipment common to all light aircraft. The geophysical instruments are passive detectors and emit no signals of any type.

Is Tellus South West carrying out other surveys?

Yes; a ground-based survey of stream sediments and waters was carried out in 2012 and early summer 2013. This used teams of volunteers to collect samples, which are now being analysed for up to 55 chemical elements and compounds.

The results will be useful for assessing the health of the environment, agricultural nutrients and trace elements. In July 2013, a higher altitude airborne survey was carried out using high precision laser range-finding technology to make highly accurate maps of ground elevation and topography, and the height of the tree canopy.

These data help us make better maps of areas prone floods, landslides and soil erosion, and to measure how much carbon is taken out of the atmosphere by growth of trees and vegetation. Both surveys have now been completed.

Who is paying for this project?

Tellus South West is financed by the Natural Environment Research Council (NERC), which funds world-leading environmental science in research centres and universities across the UK.

Who is doing the work?

The project is being managed and delivered by a partnership of the Natural Environment Research Council’s research centres — the British Geological Survey, the British Antarctic Survey and the Centre for Ecology & Hydrology — working locally with the University of Exeter Camborne School of Mines.

The partnership will continue to grow as new data and results are released by the project.

Where can I get more information?