Lunisolar body tides speed up plates?

Since more than a century of geophysical and tectonic observations, studies give us a partial view of the dynamics of the Solid Earth, which most of the scientific community today interprets in the light of plate tectonics. However, many questions are still open. One of the most intriguing matter concerns the causes and the driving mechanisms of plate motions, which are a fundamental problem for the understanding of all the geological phenomena we observe on our planet. For years it has been preferred to leave out some inconsistencies between theoretical models and experimental data, among these the “westerly” polarization of the movement of the plates with respect to the mantle and the asymmetry of subduction zones remains completely unexplained. Lunisolar tides have often been invoked to trigger plate tectonics and earthquakes, but not straightforward correlation has ever been proven. In recent decades models of astronomically tuned tectonics have been developed, giving rise to a lively debate in the scientific community. In this work an analysis of the relative motions of the main plates will be performed, in search of one possible lunisolar tidal modulation. In particular we plan to perform both short and long period analysis of baselines bridging two tectonic plates measured by geodetic techniques: GNSS, Satellite Laser Ranging (SLR) and Very Long Baseline Interferometry (VLBI) data will be analyzed in order to check whether such lunisolar tidal modulation is really present. Long period harmonic analysis now is made feasible since we now have a lot of geodetic stations all over the world for which data time series span up to 20-30 years. Moreover, data of plate motions recorded by GPS stations are routinely filtered by the theoretical tide. The goal of our analysis will focus on cross-correlating different frequencies of the lunisolar tidal modulation, tidally unfiltered space geodesy data and seismicity.