Analogue modelling of subduction: yesterday, today and tomorrow.

The use of experimental tectonics (also known as analogue-, laboratory, or physical modelling) to study tectonic processes is not a novelty in Earth Science. Following Sir James Hall’s pioneer work (1815), many modellers squeezed, stretched, pushed and pulled a wide range of materials – e.g., sand, clay, oil, painters’ putties, gelatins, wax, paraffin, syrups, polymers – to unravel a wide range of tectonic processes to determine parameters controlling their geometry, kinematics and dynamics. However, only recently experimental analogue modelling has definitively transformed from a qualitative to a quantitative technique, thanks to appropriate scaling relationships, the improvement in the knowledge of the rheology of both natural and analogue materials and the use of high-resolution monitoring techniques to quantify morphology, kinematics, stress, strain and temperature.

Here, I specifically review the experimental work performed to study one of the most intriguing aspects of plate tectonics: the subduction process. Subduction provides the dominant engine for plate tectonics and mantle dynamics. Moreover, it has also societal importance playing a key role on hazard at short (i.e., earthquakes and mega-earthquakes, tsunami, effusive and explosive volcanic activities with impact on aviation safety) and long time scales (i.e., local and global climate change). Over the last decades, a noteworthy advance in the quality and density of global geological, geophysical and experimental data has allowed us to provide systematic quantitative analyses of global subduction zones and to speculate on their behaviour. These constraints have been integrated into a mechanical framework through modelling.

I will bring you to a journey through the past, the present and the future of analogue modelling and related efforts, results and perspectives for the study of the subduction process. It will be shown how analogue models, with their inherent 3D character and behaviour driven by simple and natural physical laws, contribute to successfully unravelling the subduction process, inspiring new ideas. Challenging ongoing perspectives of analogue models imply the possibility to compare time and space scales, allowing to merge, within the same model, both short- and long-term and shallow and deep processes.