Subduction with Variations in Slab Buoyancy: Models and Application to the Banda and Apennine Systems

摘要: Temporal variations in the buoyancy of subducting lithosphere exert a fi rst-order control on subduction rate, slab dip and position associated volcanic arc. We use semi-analytic, three-dimensional model to simulate “unforced” subduction, which trench motion is driven solely by buoyancy. Model rates respond almost immediately changes entering trench; as more buoyant segments correlate with slower steeper dip. The results are largely consistent observations from Banda southern Apennine systems, where slowed ended shortly after entry continental into trench. Over 2 m.y. period, decrease 70 mm/year 30 for Arc, 40 mm/ year 20 Arc. Increases decreases arc-trench distance likewise hypocenter locations arc along Sunda arcs. In contrast, time period 10 needed slow near zero, much longer than 3 upper bound observed slowing cessation systems. One possible explanation that break-off, or formation large windows, occurred during last stages eliminating toroidal fl ow around allowing steepen rapidly its final