Figure 2
Distributions of composition (a), temperature (b), density (c) and electrical conductivity (d) for a presumed subduction zone at depths of 40 to 200 km. The composition of the asthenospheric mantle has 15% more Grt and 15% less Opx than the lithospheric mantle. The water content changes from 50 ppm in the lithospheric mantle to 420 ppm in the asthenospheric mantle. The temperature and density distributions are modeled by TEMSPOL24. The electrical conductivity distribution is calculated by a previously proposed method38 and described in the text; the effective viscosities in (e) to (g) are transformed from eq. (5) with the parameters shown in Table 1; (h) shows the curves for effective viscosity versus depth at distances of 150, 350, 550 and 750 km along the model surface. Note that it is plausible that the three calibrated relations are inappropriate in a low-temperature domain (<300 °C), which may promote the effective viscosity in the interior of subduction plate.
