-12 I I I
-14
-16
-14 -
20
-20- -
< Group 2 (underthrustlincoming)
--- logk =-19 B6 +446n; (R2 D 64)
-22 Group 2 (prismidecollement)
log k = -21 DO + 9 33n, (R2 = D 91)
-24 I I I I 1
0 02 04 06 08 1
Porosity
Figure 2-8. Permeabilities classified based on structural domain. Permeability-porosity
relationships only shown for underthrust/incoming samples (dashed line) and
prism/decollement samples (solid line) of Group 2.
The prism/decollement sediments group only contained eight samples and thus,
gave a relatively high R2 value of 0.91. The underthrust/incoming sediment group
contained twenty-two samples and showed moderate correlation between permeability
and porosity with a R2 value of 0.64. Even with the limited data available, the two
relationships exhibited similar permeabilities at lower porosity values (0.2-0.3). With
increasing porosities the two relationships predicted permeabilities that diverge from each
other. For example, the permeability-porosity relationship of prism/decollement group
predicted a permeability value of 1 x 10-16 m2 at a porosity value of 0.50 while at the
same porosity level the underthrust/incoming group predicted a lower permeability value
of 1 x 10-18 m2. The differences exhibited in these two permeability-porosity
relationships, while inconclusive, suggest that it might be useful to study more samples
representing each group, particularly the prism/decollement group, to test the predicted
relationships.