4:45 PM - 5:00 PM
[SCG57-12] Dynamics of back-arc spreading
Keywords:subduction zones, slab-mantle interaction, numerical model
Most results show periodic change in slab geometry and back-arc spreading rate and their period changes with the parameters. The result for a low maximum yield stress (200 MPa) shows tightly folded slab geometry. The result for a high maximum yield stress (800 MPa) shows relatively flat slab geometry and continuous back-arc spreading. As geological observations show that most back-arc basins formed by 10-20 Myr spreading and the tightly folded slab has not been reported by seismic tomography, we think that the result for a moderate maximum yield stress (500 MPa) reproduce the processes in subduction zones well. We compare the results of simulations with the slab geometry and the history of back-arc spreading in the Izu-Bonin-Mariana subduction zone, and discuss the condition for the start and end of back-arc spreading.