Warm relations in the bitter cold!

By Professor Stuart Marsh, Professor of Geospatial Engineering at The University of Nottingham

Over the past two years, collaboration has been growing between GERC Earth Observation scientists, Stuart Marsh and new appointee Stephen Grebby, and their counterparts in the Virginia Centre for Coal and Energy Research, Nino Ripepi and Ellen Gilliland. Nottingham have developed a satellite radar technique for measuring ground motion that offers promise in vegetated terrain but need test sites for trials. Virginia Tech have a large test CO2 injection facility with ongoing injection that needs monitoring… put the two together and a collaboration was inevitable. But how to take it forward? With hectic teaching commitments in term time, the way forward was a collaborative visit in the holidays, and so a trip was booked for 5th to 10th January. We left the comparative warmth of the UK and pretty soon had arrived in the depths of winter… or so we thought!

Leading up to the weekend, very productive discussions were held. The preliminary monitoring results looked interesting, but inconclusive. The technique relies on the build-up of a large number of satellite observations and so it looks like we will need to monitor the injection process for a while longer in order to generate reliable results. This is particularly challenging terrain for a radar-based approach, with deeply incised valleys leading to radar shadowing effects – one of the attractions of using it as a test site. Despite this, we do appear to be getting good coverage of points and so, with the further data acquisitions that are planned, a clearer picture should emerge. We were left looking forward to a visit to the injection site at the weekend…

On Friday night, the depths of winter deepened considerably! There was snow and the temperature dropped to ten below freezing! The trip to the test site was off – there was no way we would be able to get there as the mountain roads would be impassable. In fact, it was so cold that being outside for more than a few minutes at a time was not advisable. Sanctuary was sought in various sports bars and, with it being the Wild Card Weekend in the American Football, there was plenty to entertain us!

After the weekend, we switched out attention to a second site. Oklahoma has been the centre of attention recently, due to a rise in the frequency of earthquakes coinciding with an increase in the use of hydraulic fracturing to extract shale gas. Back at base, colleagues had been processing the Oklahoma data and it arrived with us in Virginia that weekend. We spent part of the next week looking at the results, which showed significant ground motion associated with some of the main extractive areas and significant seismic events. Ellen and Nino sourced various datasets to do with groundwater, production and so forth and we began to analyse the correlations in more detail. This work is continuing now that we are back at base via teleconference and emails. A significant paper looks likely to emerge from this analysis in the near future.

Pretty soon, it was time to go back to the airport and be on our way to warmer climes. But not before a farewell dinner in the Bull and Bone restaurant! As you can see from the photograph, it might have been freezing outside but UoN-VT relations were warming up nicely…

Dr Stephen Grebby and Prof Stuart Marsh with VT colleague Dr Bahareh Nojabaei and her husband at the Bull & Bone

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