The effects of plateau subduction on plate bending, stress and intraplate seismicity

The influence of subducting plateaux on inter-plate earthquakes has been extensively studied. However, its effects on plate bending, stress distribution and intraplate earthquakes remain unclear. Here we model the deflection of a subducting oceanic plate with an oceanic plateau regarded as a high flexure rigidity body near the trench using a thin plate model. Dozens of models were carried out to study the effects of the distance between plateau and trench on flexural bending and stress with variable flexural rigidity. We find that the influence of plateau depends on its location with respect to the trench axis and it begins to affect the plate bending when its distance from the trench axis is similar to 70-120 km. It changes the bending stress distribution and causes concentrated deformation to the trench-ward of the plateau. After the plateau starts to subduct, pre-existing bending faults may be reactivated by the differential forces caused by the lateral variation in slab buoyancy between the shallower seamounts/plateaus and the deeper slab.