Infrared measurement of soils

The BGS is evaluating the use of infrared spectroscopy to examine the microscopic structure of different rocks and soils and to determine their engineering properties. By measuring the pattern of light reflected from a soil surface, we can tell a great deal about its mineralogy, structure and moisture content.

Using samples taken from the Black Ven landslide complex on the coast of Dorset, England, we are developing spectral techniques that may be used to calibrate satellite imagery. As part of a research programme carried out with the University of Portsmouth, BGS staff collected samples of landslide debris from the active landslide.

Black Ven Landslide Complex, West Dorset, England.
Spectral signature of the Upper Greensand Formation at Black Ven.

We measured the infrared and visible light reflected from each sample. This information was analysed to discover the mineral composition and basic engineering properties of the landslide debris in the landslide complex.

Analysis of this has demonstrated that each material in the landslide complex can be easily identified by their spectral signature, which can be used to measure how much water they contain.

Importantly, these data can be combined to make a soil moisture index, which tells us how close to failure, and how dangerous the landslide material is and eventually could provide an early warning system for the many large debris flows that are active across Europe.

Soil moisture index of samples taken from the Black Ven landslide complex.

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