Crushed resistance

The model offers new insights into how the plate subducted under Japan breaks into segments by bending and thereby crushing olivine grains on its underside. (Graphic: Taras Gery / ETH Zurich) - Geophysicists can use a new model to explain the behaviour of a tectonic plate sinking into a subduction zone in the Earth's mantle: the plate becomes weak and thus more deformable when mineral grains on its underside are shrunk in size. The Earth's surface consists of a few large plates and numerous smaller ones that are continuously moving either away from or towards each other at an extremely slow pace. At the boundaries of two plates, the heavier oceanic plate sinks below the lighter continental plate in a process that experts call subduction. For a long time, though, those experts have been puzzling over what happens to the plate margin that dives into the Earth's mantle, known as the subducting slab. Some scientists assumed that the slab remains as rigid and strong as the plate itself and simply bends due to the gravity force and mechanical interaction with the Earth's mantle. Heavily deformed plate margin.