HR: 0830h
AN: S21E-0351    [PDF]
TI: Initiation of subduction by small-scale convection
AU: * Solomatov, V
EM: slava@nmsu.edu
AF: New Mexico State University, Department of Physics, Las Cruces, NM 88003 United States
AB: Initiation of subduction by small-scale convection is investigated with the help of Fowler's theory, numerical constraints on the lithospheric stresses generated by convection and direct numerical simulations of subduction. The derived scaling laws suggest that the critical yield stress for initiation of subduction by small-scale convection is of the order of 30 MPa. On the one hand, this value is at least one order of magnitude smaller than the estimates of the lithospheric strength suggested by laboratory experiments on dry rocks. This implies that initiation of subduction must be very problematic under conditions different from those existing on the present-day Earth which has plenty of water and globally occurring plate tectonics. On the other hand, the critical yield stress for initiation of subduction by small-scale convection is comparable with the critical yield stress for initiation of subduction by plate forces and with the estimates of stresses in the subduction zone. Thus small-scale convection can play an important role in the initiation of subduction on the present-day Earth.
DE: 7218 Lithosphere and upper mantle
DE: 8121 Dynamics, convection currents and mantle plumes
SC: Seismology [S]
MN: 2003 Fall Meeting