We report data on the curvature RC, rate of subduction vc and slab dip &agr; for 28 convergent boundary segments of oceanic plates. Slowly converging plates (vc<5 cm/yr) are associated with arcs having RC<10¿, while more rapidly converging plates produce arcs with RC ranging from 10¿ to greater than 90¿. This provides a way of estimating former convergence rates of extinct arcs. Slab dip &agr; is independent of vc for vc<10 cm/yr; the inverse relation between &agr; and vc proposed by Luyendyk (1970) is not substantiated by our larger data set. Slab dip and arc curvature are not corrected.