The NEWTON-g Gravity Imager: Toward New Paradigms for Terrain Gravimetry

Knowledge of the spatio-temporal changes in the characteristics and distribution of
subsurface fluids is key to properly addressing important societal issues, including:
sustainable management of energy resources (e.g., hydrocarbons and geothermal
energy), management of water resources, and assessment of hazard (e.g., volcanic
eruptions). Gravimetry is highly attractive because it can detect changes in subsurface
mass, thus providing a window into processes that involve deep fluids. However, high
cost and operating features associated with current instrumentation seriously limits the
practical field use of this geophysical method. The NEWTON-g project proposes a
radical change of paradigm for gravimetry through the development of a fieldcompatible
measuring system (the gravity imager), able to real-time monitor the
evolution of the subsurface mass changes. This system includes an array of lowcosts
microelectromechanical systems-based relative gravimeters, anchored on an
absolute quantum gravimeter. It will provide imaging of gravity changes, associated with
variations in subsurface fluid properties, with unparalleled spatio-temporal resolution.
During the final ∼2 years of NEWTON-g, the gravity imager will be field tested in the
summit of Mt. Etna volcano (Italy), where frequent gravity fluctuations, easy access to
the active structures and the presence of a multiparameter monitoring system (including
traditional gravimeters) ensure an excellent natural laboratory for testing the new tools.
Insights from the gravity imager will be used to i) improve our knowledge of the causeeffect
relationships between volcanic processes and gravity changes observable at the
surface and ii) develop strategies to best incorporate the gravity data into hazards
assessments and mitigation plans. A successful implementation of NEWTON-g will
open new doors for geophysical exploration.