The Earth’s interior, particularly the Earth’s fluid outer core, possesses a broad dynamics of processes involving mass variations. Theoretical models predict variations of the gravity field at low degrees and at inter-annual / decadal time scales. These include dynamic pressure changes at the Core Mantle Boundary (CMB) associated with core flows reconstructed from geomagnetic observations and reorientation of the inner core controlled by gravitational coupling with the mantle. The hypothetical effects due to some dissolution/crystallization at the CMB introduce a time-varying roughness of the interface. Taking into account these considerations, for the first time, we investigate the density and pressure changes obtained from magneto-hydro-dynamics (MHD) simulations that reproduce geomagnetic jerks.

Besides the geomagnetic information, we also are interested in exploiting long series of gravity measurements. The time-variable Earth’s gravity field is measured by satellite missions such as GRACE and GRACE Follow-On and by Satellite Laser Ranging (SLR). These products enable to study continental hydrology, oceanic and atmospheric loading, post-glacial rebound, glaciers, earthquakes and other phenomena that involve mass variations. The comparison of GRACE and SLR gravity field variations with Earth’s core predicted signals gives new inputs on parameters of the Earth’s core processes. This study provides new upper-bound values for pressure anomalies at the CMB and angle of reorientation for the inner core.