When a slab slides beneath an overriding plate in a subduction zone, the slab takes on a property called anisotropy, meaning its strength is not the same in all directions. Anisotropy is what causes a wooden board to break more easily along the grain than in other directions. In rock, the alignment of minerals such as clay, serpentine, and olivine can lead to anisotropy. Pockets of water in rock can also cause and enhance anisotropy, as repeated dehydration and rehydration commonly occur at depth in a subducting slab.
New earthquake model goes against the grain
