Dips of Downgoing Lithospheric Plates Beneath Island Arcs

TLDR: In this paper, the authors measured the dip of downgoing lithospheric plates by inspecting published vertical sections of relocated hypocenters beneath Pacific and Indian island arcs and found that the maximum dip of the slab in a particular section, as determined by the hypocenter configuration, is inversely proportional to the distance from the section to the pole of relative motion of the two plates involved.

Abstract: Dips of downgoing lithospheric plates were measured by inspecting published vertical sections of relocated hypocenters beneath Pacific and Indian island arcs. For any one arc the maximum dip of the slab in a particular section, as determined by the hypocenter configuration, is inversely proportional to the distance from the section to the pole of relative motion of the two plates involved. Considering several oceanic arcs, a common inverse relationship exists between the dip and the relative rate of convergence of the plates at the location of the measurement. This dip-rate relationship may be a manifestation of the heavier downgoing plate that is sinking to an equilibrium (vertical) position.