70 Years of Earth Observation at the British Geological Survey / / by Colm Jordan

Colm Jordan is Head of ‘Geodesy and Earth Observation’ at the British Geological Survey. In this role he leads development of airborne and satellite systems to help us understand how our Earth works, and how we interact with it. He is also a qualified commercial drone pilot!

The BGS Space GeoDesy Facility at Herstmonceux

Earth Observation (often shortened to EO, or called remote sensing) is when we use sensors on the ground, on drones / aircraft, or on satellites to map our planet and understand the complex geological processes that affect our lives and livelihoods. Modern sensors allow us to see things invisible to the human eye; for example we can see heat signatures or even use radar systems to map millimetre changes to the Earth’s surface from space.

Scientists working at the British Geological Survey (BGS) use Earth Observation every day, but this wasn’t always the case. This year we celebrate 70 years since the first Earth Observation team was established at the BGS. In 1949 a Photogeology Section was created in the Directorate of the Colonial Geological Survey, which is what the BGS was called then. The 1950 Annual Report describes that the main objective of the Section was ‘to prepare photo-geological maps of Colonial territories’. Initially there was only one member of staff, but by 1956 there were five people working in the Section. In addition to their own photogeological work, they trained people from Geological Surveys overseas, and because the subject wasn’t taught in many university geological courses, they gave special lectures to geological students in the UK.

1940s stereo pair of Royal Air Force air photos of volcanic cones and lava flows near Mzima Springs in Kenya. Reproduced from Stringer, 1951

The quarterly bulletin of the Colonial Geological Survey (Vol 1, No 2, 1951) describes one of the first projects in the Photogeology Section. Geologists used air photos acquired by the Royal Air Force to make geological maps of volcanic cones and lava flows near Mzima Springs in Kenya. The air photo pairs (Figure 1) were viewed with a stereoscope to see the landscape in 3D.

Nowadays, the Geodesy and Earth Observation team at the BGS has access to - and helps to develop - tools that the original Photogeology Section could only have dreamt of. For example, we have handheld instruments that measure the spectral properties of rocks, we develop and fly drones with gas, thermal and multispectral sensors, and we use a wide range of data from satellites that routinely collect images of the entire planet. 

Infrared satellite image of the same area as figure 1. Copernicus Sentinel Data (2019) processed at BGS

Figures 2 and 3 are example images from the European Space Agency Sentinel-2 satellite showing the same location in Kenya as in the 1940’s air photos. At BGS we processed the images to include the infrared portion of the spectrum because it helps us to differentiate rock/soil types. In this example it is easy to pick out the lava flows. In 1949 our predecessors were limited to the black & white photographs but with modern satellite images like this we can zoom into see detail and then zoom out to get a more regional view of the geology.

Modern satellite images help us to understand geological processes in the UK and in remote locations across the world that are costly or difficult to access. They are particularly useful when responding to disasters (e.g. landslides and tsunamis) where the imagery can be used to gain an understanding of the situation very quickly (sometimes in a matter of hours) and to provide advice to relief organisations or governments. 

Regional infared satellite image of the area. Copernicus Sentinel data (2019) processed at BGS

Did you know that BGS even has a Space Geodesy Facility at Herstmonceux that uses laser ranging to accurately track satellites?

For more information about the science of Geodesy and Earth Observation (and the team of eight specialists) at BGS, please visit the website.

Thanks to David Bate for finding the original Colonial Geological Survey texts and to Alessandro Novellino for acquiring the raw Sentinel-2 satellite image.