Changes in the permeability, streaming potential and resistivity of a claystone from the Nankai prism under stress

Online Access: Get full text
doi: 10.1029/93GL03293
Author(s): Jouniaux, Laurence; Lallemant, Siegfried; Pozzi, Jean-Pierre
Author Affiliation(s): Primary:
Ecole Normal Supérieure, Laboratoire de Géologie, Paris, France
Volume Title: Geophysical Research Letters
Source: Geophysical Research Letters, 21(2), p.149-152. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276 CODEN: GPRLAJ
Note: In English. Ecole Normale Supérieure (ENS) Contrib. No. 309; CNRS-INSU-DBT Contrib. No. 662 thème instabilités. 18 refs.; illus.
Summary: Permeability is the critical factor governing fluid flow in accretionary prisms. Accretionary wedges are highly deformed, so permeability changes in an indurated claystone sample from the Nankai accretionary prism were measured during a triaxial stress experiment by the pulse decay method. Three zones were identified from the loading test. In zone I, the sample has deformed less than 1.3% and its permeability was 5.10-20 m2. In zone II, the deformation reached 1.5% and the permeability was unstable with time. In zone III, the sample deformation reached 2% and its permeability reached 3.8 10-18 m2. The permeability strongly decreased (from 3.2 10-18 m2 to 1.7 10-19 m2) with increasing effective pressure (from 2.3 to 10.8 MPa) after the sample was well deformed (zone III). The streaming potential was not measurable when the sample had a low permeability (zone I), but clearly occured when the permeability increased (zone III) : the streaming potential measured was 6 mV when the pore pressure pulse applied was about 1.17 MPa and the permeability 3.8 10-18 m2. Our experiments suggest that shear deformation under low effective pressure increased the vertical permeability of sediments above the décollement. This increase in permeability may be detected by measuring the streaming potential. Variations of flow rate of expelled fluid in accretionary wedges may be detected by monitoring changes of electrokinetic potential, giving new insights on the state of stress related to the seismic cycles. Copyright 1994 by the American Geophysical Union.
Year of Publication: 1994
Research Program: ODP Ocean Drilling Program
Key Words: 16 Structural Geology; Accretionary wedges; Clastic rocks; Claystone; Deformation; Electrical properties; Electrofiltration potential; Electrokinetic potential; Fluid phase; Igneous rocks; Leg 131; Leg 132; Loading; Movement; Nankai Trough; Nankai accretionary wedge; North Pacific; Northwest Pacific; ODP Site 808; Ocean Drilling Program; Pacific Ocean; Permeability; Pore pressure; Pore water; Pressure; Pyroclastics; Resistivity; Sedimentary rocks; Stress; Triaxial tests; Tuff; Volcanic rocks; West Pacific
Coordinates: N322105 N322111 E1345646 E1345634
Record ID: 1994054419
Copyright Information: GeoRef, Copyright 2019 American Geosciences Institute.