northern Barbados accretionary complex which shows at least 50 m offset in the
turbidites along the normal faults extending upward from the basement (Zhao and Moore,
1998) suggesting that vertical hydrofracture could occur in the underthrust. According to
Behrmann (1991), the criteria requires X* to be > 0.8 for vertical hydrofracturing in soft
rocks. Vertical hydrofractures occur perpendicular to the least principle stress axis.
According to Price (1975), when sediments hydrofracture, the hydraulic properties are
expected to change dramatically.
Modeling Methods
Model Implementation
A model developed by Screaton and Ge (2000) was modified to simulate the effects
of subduction beneath a prism. This model builds the accretionary complex in segments
through time. The prism growth/flow model consists of two sub programs. The first sub
program is a modified loading program (Gamage and Screaton, 2006), which builds the
initial sediment column that enters the accretionary complex at the deformation front.
The second sub program (prism loading) advances the accretionary complex over the
subducting sediments in segments through time at a convergence rate of 2 cm/yr. It is
assumed that the taper of the prism is constant. The prism-growth/flow model calculates
the time necessary for prism to advance one column by dividing the horizontal dimension
of the column by the convergence rate. The vertical dimension is calculated using the
prism thickening rates. As the prism advances seaward the loading program adds
sediments on each advanced column according to the assigned prism thickening rates.
Based on the calculated increase in overburden and sediment properties, the prism-
growth/flow model calculates the pore fluid pressures. These pore pressures are then
input into SUTRA (Voss, 1984), a finite-element code that simulates transient two-