Tidal triggering of earthquakes in diverse tectonic settings has been well documented, albeit the mechanisms and implications remain elusive. Here we present solid earth and ocean tide modulation of micro-seismicity, associated with caldera dynamics of the 2015 axial seamount eruption in the Juan de Fuca ridge, from well-monitored micro-seismicity catalog of mid-ocean ridge volcanoes to gain an insight into the complex interplay between volcano-tectonic and external influence of periodic tidal loading. We report a significantly strong semi-diurnal tidal periodicity in pre-eruption and weak semi-diurnal tidal periodicity in the post-eruption phase, which converge with the statistical correlation with the tidal stress. We propose that during the pre-eruption stage, fault systems are critically stressed and more sensitive to stress perturbation by periodic tidal loading. However, during the eruption stage, volcano-tectonic processes dominated masking the tidal modulation in micro-seismicity. The unusual micro-seismicity modulation during pre-eruption magma chamber inflation and reactivation of normal faulting, explicitly during the lowest tide, can be explained by a complex interplay between magma chamber inflation and periodic tidal loading, with eventual feedback mechanism on the caldera ring fault system.