Absolute Gravity Measurement: A New Perspective for Geodynamic Studies

ABSTRACT: To study gravity changes associated with tectonic deformation due to pre, co and post seismic processes; post glacial rebound; tides, influence of atmosphere and the hydrosphere, an accuracy of 2 parts in a billion of gravity field (20nms-2 or 2 micro gals) is required. This precession of measurements can be achieved with new developed FG-5 absolute gravity meter. This provides an opportunity to understand geodynamic processes causing gravity changes. National geophysical Research Institute (NGRI), Hyderabad has taken an initiative to start absolute gravity measurements with collaboration of Department of ocean Development (DOD) in India and established first absolute gravity value of an accuracy of 2 micro-Gals. The instrument will now be deployed for crustal deformation studies, establishing reference absolute gravity bases and tidal monitoring etc. In order to achieve an accuracy of ~2 micro-Gals, several precautions in the observations are required. In this paper we discuss about the principle; operation and observations of absolute gravity measurements