(Table 1) Results of permeability testing of sediments from ODP Site 131-808A

Coring at ODP Site 808 successfully recovered a sequence of accreted and subducted sediments from the toe of the Nankai convergent margin. Detailed physical properties measurements revealed a systematic downhole consolidation trend, punctuated by two main offsets: a thrust fault at 365 mbsf and a décollement near 950 mbsf. Sediment dewatering during the accretion and subduction processes are strongly influenced by the permeability of the sediments. Results of over 60 permeability measurements made on subsamples of Site 808 cores reveal coefficients of permeability ranging from 10**-5 to 10**-10 cm/s (10**-14 to 10**-19 m**2) in horizontal and vertical directions. The generally low permeability of sediments at the depth of the décollement must influence the stress-strain behavior of this major structural horizon.