THE THERMAL REGIME OF A 3-DIMENSIONAL SUBDUCTING LITHOSPHERIC SLAB AND ITS ELECTROMAGNETIC RESPONSE - A NUMERICAL-MODEL

A three-dimensional subducting lithospheric slab is simulated by a num erical technique and its temperature regime investigated. A single-sla b model or models with multiple slab sections can be considered. An ex ample is shown of two slab sections that dip at different angles. The near-surface heat flow above the slab is considered, and compared with a two-dimensional model. The temperature changes of particular points within the slab are monitored as it subducts and compared with the tw o-dimensional case. Considerable differences exist between the two- an d three-dimensional cases, depending on the location of the point cons idered. An electromagnetic model is derived from the thermal model and the perturbations of time-varying electromagnetic fields caused by th e electrical resistivity variations associated with the temperature va riations are investigated.