Volcanic eruptions pose a severe threat to life and property on a global scale. In order to mitigate risks it is essential to assess hazards of volcanic activity by evaluating results obtained from detailed monitoring and quantification of volcano dynamics. Towards this end, the proposed research aims to investigate poorly understood volcanic processes associated with sub-surface mass and/or density changes using a new type of gravity survey. A new gravity meter, developed at the Open University, enables the continuous measurement of the absolute value of gravity. The gravity meter may be operated within a network of such instruments, dramatically improving the temporal, spatial and safety limitations of conventional gravity surveys on active volcanoes. Detailed real-time 3D mapping of sub-surface mass changes have never been available before. With this new instrument, the size and shape of mass changes and, significantly, the rate of change can be determined. The research will target volcanic calderas and persistently active volcanoes. The project focuses on the investigation and quantification of processes occurring within the magma reservoir and the conduit both before and during an eruption. The initial field trials will be conducted on the Italian volcanoes Campi Flegrei, Mt. Etna and Stromboli. Outcomes from this research include insights into the dynamics of reservoir and conduit processes such as magma injection, withdrawal, convection, vesiculation and fragmentation. Their search will establish a new, exciting and low-cost volcano-monitoring tool and provide a substantial contribution towards model development for eruption forecasting. This study will undoubtedly establish a new technique that will revolutionize volcano monitoring, benefiting the academic career of the applicant and the standing of the Volcano Dynamics Group (VDG) at the Open University. The applicant will be trained in micro-gravity technology and instrument development by working within one of the most productive and internationally respected micro-gravity groups in the world. The applicant's expertise in magma rheology will provide essential constraints on magma chamber and conduit models developed by researchers within the VDG. Theproject represents a substantial step forward in understanding and quantification of volcanic rheologicalprocesses providing the first opportunity to obtain real-time gravity data across a network at a frequency of 1 Hz or 1 per day rather than 1 per week/month/year typically attained during conventional surveys. Thus we will be able to i) test existing models developed in the VDG and elsewhere and ii) foster the further development of new models to interpret mass/density changes beneath volcanoes for hazard assessment.