A Possible Roll-Over Slab Geometry Under the Caroline Plate Imaged by Monte Carlo Finite-Frequency Traveltime Inversion of Teleseismic SS Phases

The shape of a subducting slab varies as function trench motion. Two end-members subduction modes are geodynamically possible: roll-back mode underneath neighboring plates and roll-over the plate itself. Whereas most major slabs seem to roll back while Pacific shows piling behavior down ∼1,000 km depth under Mariana trench, no clear evidence in nature has been reported so far. Here we show possible beneath Caroline microplate, revealed from its three-dimensional seismic velocity structure derived by analyzing teleseismic reverberating SS phases. We suggest that is driven at least two factors: 1) overall buoyancy fragility microplate surface, induced thin hot mantle plume rises depths ≥800 km; 2) pushing force acting on trailing edge plate.