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TitleSimplified analysis of horizontal stresses in a buttressed forearc sliver at an oblique subduction zone
AuthorWang, K
SourceGeophysical Research Letters vol. 23, no. 16, 1996 p. 2021-2024,
Alt SeriesGeological Survey of Canada, Contribution Series 1996157
Alt SeriesGeological Survey of Canada, Contribution Series 31395
Mediapaper; on-line; digital
File formatpdf
ProvinceWestern offshore region
AreaPacific Ocean; Canada; Japan
Subjectstectonics; subduction; oceanic crust; plate margins; stress analyses; tectonic environments; tectonic elements; tectonic interpretations; tectonic models; modelling; Juan de Fuca plate; Pacific plate; Coast Mountains; Hidaka Mountains
Illustrationssketch maps; models
Released1996 08 01
AbstractForearc slivers are commonly present at obliquely convergent margins. Such slivers are often buttressed at their leading edges, but no quantitative model of the buttress effect exists. I consider the horizontal stresses in a buttressed sliver using a simple plan-view two-dimensional elastic model. The driving force created by the subducting plate is approximated by a body force in the direction of plate convergence. An Airy stress function solution relates the stress field to the boundary and body forces that allows the relative importance of different forces driving and resisting the sliver to be evaluated. Oblique subduction can easily cause arc?parallel compression in the buttressed sliver, especially near the leading edge, because the arc?parallel component of the driving force by the subducting plate is integrated over a much larger distance than its arc-normal component. For the Southwest Kuril arc, the stress field predicted by the simple model agrees with that inferred from geological structures. It is possible that the model can also explain the stress field of the Cascadia forearc as constrained by earthquake focal mechanisms and in situ stress measurements.