Open AccessSlab pull effects from a flexural analysis of the Tonga and Kermadec trenches (Pacific Plate)
Author(s) -
GarciaCastellanos Daniel,
Torne Montserrat,
Fernàndez Manel
Publication year - 2000
Publication title -
geophysical journal international
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.302
H-Index - 168
eISSN - 1365-246X
pISSN - 0956-540X
DOI - 10.1046/j.1365-246x.2000.00096.x
Subject(s) - lithosphere , geology , slab , lithospheric flexure , seismology , flexural strength , deflection (physics) , pacific plate , brittleness , bathymetry , bending of plates , ultimate tensile strength , plate tectonics , geophysics , subduction , bending , tectonics , materials science , composite material , optics , oceanography , physics
Thin‐plate flexure models have been frequently used to explain the mechanical behaviour of the lithosphere at oceanic trenches, but little attention has been paid to using them as a way to check the relative importance of different plate‐driving mechanisms. A 2‐D numerical algorithm accounting for the flexural deflection of the lithosphere controlled by multilayered elastic–plastic rheology (brittle–elastic–ductile) has been applied to the seaward side of the Tonga and Kermadec trenches. This approach gives a better fit to the bathymetry on both trenches than assuming classical homogeneous plate models, and allows the interplate coupling forces and the lithospheric strength profile to be constrained. Our results show that, in order to fit the observed deflection of the lithosphere, a regional tensile horizontal force must act in both regions. This tensile force and its flexural effects are discussed in terms of slab pull as a main plate‐driving mechanism. The predicted stress and yielding distributions partially match the outer‐rise earthquake hypocentres within the subducting plate, and thus do not invalidate the model.