temperature distribution. Both the seafloor and oceanic crust boundaries were treated as
specified temperature boundaries. The seafloor boundary was set at 2 C while the heat
flow at the base of the model was assigned to produce temperatures consistent with those
obtained from shipboard measurements. Thermal conductivities and specific heat values
for both fluid and solid matrix are given in Table 3-2. SUTRA then calculated fluid
viscosity as a function of temperature using the following relationship (Voss, 1984)
248.37
p(T) (239.4*10 10 0 (T+133"15) (13)
where p is pore fluid viscosity [kg m-s-1] and T is temperature in C.
Table 3-2. Fluid and solid matrix properties used for numerical simulations.
Parameter Value
Fluid compressibility [Pa-1] 4.40E-10
Fluid density [kg m-3] 1035
Fluid specific heat [J kg-OC-'1] 4180
Fluid thermal conductivity [J s-' m-1 "C-1] 0.7
Solid grain density [kg m-3] 2650
Solid grain specific heat [J kg-'lC -] 1000
Solid grain thermal conductivity [J s-1 m-1 C-1] 3.0
Sedimentation and Prism Thickening Rates
Sedimentation seaward of the deformation front and loading due to the over-riding
prism were applied separately in two different phases (Table 3-3). During phase one,
sedimentation rates calculated from the biostratigraphy were used to build the sediment
columns at Sites 808, 1174, and 1173. At Site 808 and 1174, the sediment columns were
built using 137 time steps of 100,000 years and at Site 1173, 140 time steps were used.
The average initial sedimentation rate for each unit was based on the initial thickness of
that unit and its corresponding deposition time as provided by the Shipboard Scientific
Party (2001). The initial thickness of each unit (i.e., the thickness of the sediment layer
prior to consolidation) was calculated based on an assumed initial porosity of 0.77 and