Two-dimensional discrete element simulation of plate subduction deformation process: An insight into the genesis of East China Sea Shelf Basin

Subduction deformation is a tectonic phenomenon in the process of plates convergence, which remains a hot topic. The East China Sea Shelf Basin is located in the south-eastern border of the Eurasian plate, whose tectonic evolution and dynamic mechanism are related to the subduction of the Philippine plate and the Pacific plate beneath the Eurasian plate. At present, the research on the subduction deformation is still not so perfect, and the influence of subduction angle changes on the deformation process needs further study. The authors, in this paper, tried to use the method of discrete element simulation, a kind of emerging method in the field of tectonics, to simulate the evolution process of plate subduction deformation. By constructing discrete element models and comparing the experimental results with the strata in the subduction zone between the Philippine plate and the East China Sea, the research shows that (1) The subduction deformation characteristics are related to the subduction angle. Different subduction angles result in different deformation patterns. (2) The number of faults and the horizontal offsets of faults increase as the subduction angle decreases. Fault displacement at the same position under different subduction angles is different. (3) The height of the subduction wedge and deformation degree increases as the subduction angle decreases. And the shape of subduction wedge is different. (4) Back-thrusts form later as the subduction angle decreases. (5) Experimental simulation results have similar structural characteristics with instance. The experimental simulation results may explain the evolution process of plate subduction deformation under different subduction angles, which is helpful to further understand the subduction deformation during plates convergence process.