"Subduction zones play a fundamental role in our daily life. Half of the world population lives on top or nearby one of them, in coastal areas repeatedly devastated by large earthquakes, tsunamis or volcanic eruptions. Giant earthquakes occurring on subduction zone mega-thrusts (Mw close to 9 or larger) are indeed amongst the deadliest natural hazards. During the last decade, very large earthquakes took many lives (Sumatra, Chile, Japan) and, according to the World Bank, over 200 billion € for the 2011 Japan earthquake.These dramatic phenomena are fundamentally controlled by the mechanical coupling and global material transfer at and across subduction zone inter-plate boundaries, between the down-going subducting plate and the overriding plate. Stresses and energy release via earthquakes together with fluid-mediated mass transfer are indeed highly focused on the plate interface, where they interact on a wide range of spatial and temporal scales, both at short- (10e-4 yr) and longer time-scales (10e6 yr).However, despite its social and economic impact, the nature, structure and properties of this plate interface are still largely unknown, calling for a thorough Zoom In between the Plates (ZIP). ZIP represents a real challenge for a new generation of geoscientists and requires innovative, high-end, cross-disciplinary scientific and technologic training to provide them with the skills and strength to tackle such problems, make major contributions, and undertake an academic or industrial career on managing geohazards. This scientific effort is mandatory for risk assessment, to enhance the reliability of early-warning systems and help reduce human loss and economic costs. Educational outreach in vulnerable countries is also crucial to explain the seismic, tectonic and tsunamic processes both to politics and populations."