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Retrieving pre-seismic signals before the occurrence of great earthquakes is a critical challenge of Earth's sciences. Space geodetic observations of ground displacements and seismic data provide monitoring of seismic events and shallower aseismic motions, but the full spectrum of deformations of the subducted slab at depth remains difficult to constrain. Yet, the pulling force of the slab plays an important role in driving plate motions. Time-varying satellite gravity can overcome this observational limit, thanks to a unique sensitivity to mass redistributions at all depths and a global coverage. Taking the example of the 2011 Tohoku earthquake, we develop here a global and systematic analysis of time series of GRACE-reconstructed gravity gradients, to test whether the deep gravity signals preceeding the earthquake (Panet et al., 2018; Bouih et al. 2022) can be detected before the event as a specific feature …