Three-dimensional numerical modeling of detachment of subducted lithosphere

Recent seismological studies suggest that slab detachment has occurred in the Mediterranean and the New Hebrides subduction zones. To investigate the physical mechanism of the slab detachment and in particular its migration, a viscoelastic 3-D finite element model was constructed and introduced a small initial tear from one side of the slab. Results show that an area of high shear stress concentration of the order of several hundred megapascals forms near the tip of the tear inside the slab, which is probably sufficient to cause further lateral migration of the tear. The stress concentration increases with the length of the tear and lower viscosity values of the surrounding mantle and increases with downdip tension. -from Authors