GG-TOP: Gravity Gradient - Technologies and Opportunities Programme

Gravity measurements exert a particular fascination ranging from the everyday experience of feeling the gravitational force holding us on ground to the mysteries of general relativity and space time. Compared to other forces gravity is surprisingly weak, making shielding of gravitation practically impossible. Gravity measurements are ideally suited to look deep inside the ground and they have been used for over 100 years in fields as oil and mineral exploration, underground mapping and climate research. However, although gravity measurements are highly valued, there are some drawbacks in terms of long and tedious measurements and geological noise. GG-TOP responds to an increasingly pressing demand for a holistic development programme driving sensitivity of instrumentation, modelling instrument and geological noise, discriminating underground objects, fusing and presenting the information from multi-sensor systems.
The GG-TOP consortium is truely multi-disciplinary uniting fundamental and applied physicists, civil and electrical engineers and archaeologists behind a joint goal. GG-TOP has a strong Stakeholder compontent with interactions at all levels and potential users directly influencing the research programme. GG-TOP will explicitly evaluate the potential of its new technology in applications as diverse as urban infrastructure (pipes, cables...) and void (cellars, tunnels,..) mapping, seabed inspection, archaeology and fundamental tests of physics.
We anticipate the outcome of this programme to be a technology suite adaptable to various needs and leading to a range of follow-on product development programmes.

Unusually for a research grant that advances fundamental science and technology, GG-TOP presents a strong and direct pathway to impact. Exploration of the underground profoundly affects us all. The ground is a resource - a supplier of natural materials and even energy - and it houses much of the infrastructure on which society depends; GG-TOP will assist in identifying the resources, and highlighting difficulties associated in securing them, as well as illustrating how our underground space might optimally be used.
Its first impact is therefore assisting in understanding, with far greater precision, the ground since density variations provide the clue to the presence of natural resources, their disposition and the natural hazards (e.g. sinkholes and loosening / softening of sub-strata) that the ground might present [Geological Sciences and Mineral Resources industries impacted]. Moreover there are parts of the ground that are difficult to access and thus explore and the technology, which can be classified under the broad banner of geophysics, complements existing technologies for underwater, seabed and similar offshore exploration [Marine Science and Engineering impacted].
That ground is an exploited resource, for a variety of reasons, throughout human history is well known and precision in revealing the legacy of this anthropogenic activity provides the second major impact. The results of previous mining and quarrying are typically highly detrimental to the stability of the ground (many urban areas are still plagued with the unexpected effects of such working of the ground which cruder current technologies are unable to detect with adequate precision), while humankind has deliberately buried, or allowed to become buried, our history [Engineering Geology and Archaeology impacted].
The ground equally provides the stable foundation for what is built on it (buildings, structures) and in it (tunnels, basements, caverns), and developments in the discovery of hidden hazards such as voids and loose ground bring major economic and social benefits [Geotechnical and Structural Engineering impacted].
Moreover, we have used the ground beneath our roads to bury the utility pipelines and cables that provide the essential services to our urban areas and the records of previous burial, some being >100 years old, are incomplete and inaccurate; GG-TOP provides an additional location technology to complement current developments and facilitate trenchless and minimum dig technologies in place of trenching [Utility Service and Road Engineers impacted].
In the quest to create more sustainable urban environments there is a strong push to use underground space more extensively, thus relieving the surface for green space (trees, natural habitats to maximise biodiversity) and greater aesthetic uses; GG-TOP provides a complementary technology for underground space mapping, revealing where space might be safely, effectively and beneficially used [Urban Planners and Developers impacted].
In addition GG-TOP will have considerable impact on science at the most fundamental level [Physics and Space Research impacted]. The new high-sensitivity developed by GG-TOP will pave the way for experiments enhancing our fundamental understanding of nature. GG-TOP will help to open a new window to interrogate space time fluctuations and test quantum gravity theories. Testing quantum gravity at the low energy scale is a novel route to consolidating quantum mechanics with Einstein's general relativity, the most fundamental problem of our time.
GG-TOP would be an important ingredient to ensure that the UK plays a strong role in these.