Finite element models of spontaneous subduction initiation: preliminary results

Subduction is a key process in Earth's plate tectonics that drives plate movement through slab pull. Despite its significance, the mechanisms behind subduction zone initiation (SZI) are not fully understood, and various hypotheses have been proposed and tested over the years using numerical modelling and real data analysis. Stern (2004) proposed a classification for the subduction zone initiation (SZI) based on the causes that lead to initiation: induced SZI caused by forces away from the site and spontaneous SZI caused by forces originating on the site. Although significant progress has been made and the main focus of the research about the SZI has changed through the years, important controversies and unresolved issues stil remain, such as whether passive continental margins collapse, ideas on lithospheric failure due to prolonged interaction with plume heads, inversion of oceanic ridges, and understanding SZI from a global mantle convection perspective. In this perspective, this work is aimed to investigate the parameters controlling the spontaneous subduction initiation at a passive margin. A set of 2D finite-element numerical models have been developed with the code FALCON (Regorda et al., 2023), by varying the mechanisms involved in the simulation, the initial setting, composition and dimension of the domain, the boundary conditions and the rheological and compositional parameters of the materials involved. The preliminary results presented in this work will contribute to a wider project aimed at investigating subduction initiation through 2D and 3D finite element and finite differences modelling and the comparison of the model results with real data. References Stern R. J.; 2004, Subduction initiation: spontaneous and induced. Earth and Planetary Science Letters. Regorda A. Thieulot C., van Zelst I., Erdos Z., Maia J., Buiter, S.; 2023, Rifting Venus: Insigth From Numerical Modeling. JGR Planets.