Fluid budgets of subduction zone forearcs: The contribution of splay faults

Rachel M. Lauer, Demian M. Saffer

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13 Scopus citations

Abstract

Geochemical and geophysical evidence indicate that splay faults cutting subduction zone forearcs are a key hydraulic connection between the plate boundary at depth and the seafloor. Existing modeling studies have generally not included these structures, and therefore a quantitative understanding of their role in overall fluid budgets, the distribution of fluid egress at the seafloor, and advection of heat and solutes has been lacking. Here, we use a two-dimensional numerical model to address these questions at non-accretionary subduction zones, using the well-studied Costa Rican margin as an example. We find that for a range of splay fault permeabilities from 10-16 m 2 to 10-13 m2, they capture between 6 and 35% of the total dewatering flux. Simulated flow rates of 0.1-17cm/yr are highly consistent with those reported at seafloor seeps and along the décollement near the trench. Our results provide a quantitative link between permeability architecture, fluid budgets, and flow rates, and illustrate that these features play a fundamental role in forearc dewatering, and in efficiently channeling heat and solutes from depth.

Original languageEnglish (US)
Article numberL13604
JournalGeophysical Research Letters
Volume39
Issue number13
DOIs
StatePublished - Jul 1 2012

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All Science Journal Classification (ASJC) codes

  • Geophysics
  • Earth and Planetary Sciences(all)

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