|Satellite imagery of Mount Etna|
Over the last 25 years, it has been extensively used by earth scientists for mapping and modelling natural phenomena such as volcanoes and landslides.
I had the opportunity to do a PhD in Italy which, unfortunately or fortunately (it depending on your point of view! For a scientist, it’s a very interesting place to be), is a natural laboratory for such phenomena and hosts institutes at the forefront of InSAR research (e.g., University of Florence, National Institute of Geophysics and Volcanology - INGV).
|Ground deformation observed with InSAR and GPS over the Campi Flegrei caldera (Italy) between 2004 - 2007. (Source: Bevilacqua et al, 2020)|
On the other side, the UK is a country with limited experience of large natural disasters related to ground motion and therefore moving here has shifted my InSAR interests from natural-induced ground motion phenomena to human-induced ones such as groundwater extraction and groundwater rebound in mined areas.
BGS has decades of experience in using InSAR through several international projects, such as PROTHEGO, PanGeo and the upcoming European Ground Motion Service where I am involved in the Task Force, which defines the technical requirements of the InSAR.
These works have enabled us a better understanding of the susceptibility and hazards associated to ground motion for Great Britain.
However, we are now in what I use to call, the ‘Golden Age’ for Earth Observation.
Latest satellite constellations such as Sentinel-1, funded by the European Commission and managed through the European Space Agency, are paving the way for mapping ground instabilities at unprecedented spatial and temporal resolution.
Such wealth of information is allowing to develop new and better solutions for building a more resilient society.
One example can be seen in a work recently published in the journal Remote Sensing.
The research has developed a model for groundwater rebound in recently abandoned coalfields in Nottinghamshire using InSAR which can be used, in turn, to enable predictions of surface discharges that can support mitigation strategies.
The work has been developed by David Gee, a PhD student funded by the GeoEnergy Research Centre of the University of Nottingham and co-supervised by myself and Luke Bateson along with staff from the Coal Authority.
|Predicted time until discharge out of the Coal Measures Group between Derbyshire and Nottinghamshire (source Gee et al, 2020).|
Knowledge of the time-scales (i.e. the rate) of rebound is crucial to coalfield remediation strategies. The modelling concept developed here is able to map the change in groundwater with complete coverage, to fill in the measurement gaps between the boreholes. The data can be used by national bodies such as the Environment Agency which is responsible for managing hazards such as flooding, pollution and contaminated land, and the Coal Authority which has a mandate to manage the legacy and assets of underground coal mining in terms of public safety and subsidence. Next challenge for BGS and the wider InSAR community is to develop a (hardware and software) infrastructure system able to manage the huge volume of information (in the order of terabytes of data collected everyday over the UK only) and associated results (millions of points with ground displacement information every 6 days) needed to regularly monitor the Earth’s surface.
For more information on the BGS InSAR research, please visit our website.