Data report: permeability of mud(stone) samples from Site C0001, IODP Expedition 315, Nankai Trough: NanTroSEIZE Stage 1

Abstract

In this study, we conducted constant-flow permeability tests in the horizontal (cross-core) and vertical (along-core) directions using five whole-round core specimens of mud(stone) from Integrated Ocean Drilling Program (IODP) Site C0001. The site is located above the accretionary prism of the Nankai Trough offshore of the Kii Peninsula, Japan. The samples came from depths of approximately 25 to 290 m below seafloor and include lithologic Units I (slope apron facies) and II (upper accretionary prism). Effective isotropic confining stress during the tests was set at five increments ranging from 0.034 MPa (5 psi) to 0.551 MPa (80 psi). Average values of hydraulic conductivity range from 1.06 × 10 -8 to 7.30 × 10 -7 cm/s. Corresponding values of intrinsic permeability range from ~10 -17 to 10 -16 m 2 . The ratio of horizontal to vertical permeability (k h /k v ) averages 1.15. Environmental scanning electron microscopy was used to assess the relation between the sediment's microstructure and the anisotropy of permeability. Indicators of anisotropy generally show modestly better alignment of grains in the horizontal direction. IntroductionEarthquakes and tsunamis are among the most unpredictable and destructive natural disasters, sometimes destroying life as well as buildings on a massive scale. Particularly destructive are those earthquakes occurring in subduction zones. Recent examples include the Sumatra earthquake and tsunami in 2004 and the earthquake and tsunami off the coast of Sendai (Tohoku) Japan in 2011.To better understand how and why earthquakes and tsunamis occur in subduction zones, it is useful to measure the mechanical and hydrological properties of sediments and sedimentary rocks retrieved by scientific ocean drilling. Among those many properties, permeability has an important influence on sediment consolidation and strength through its affect on pore fluid pressure (Moore and Vrolijk, 1992; Saffer and Bekins, 2006). By characterizing hydrological properties both within and adjacent to fault zones at various depths, we can examine how geologic structures and permeability might influence one another over a range of effective stress values, thereby improving the understanding of fault dynamics.Kinoshita, M., Tobin, H., Ashi, J., Kimura, G., Lallemant, S., Screaton, E.J., Curewitz, D., Masago, H., Moe, K. In this report, we present the results of constant-flow permeability tests that were completed at the University of Missouri on whole-round core specimens retrieved from the Nankai Trough accretionary prism offshore Japan (Fig. F1) (Fig. F1). The upper three samples come from lithologic Unit I (slope apron facies), whereas the lower three are from Unit II (upper accretionary prism). Bedding dips at the sampling depths are also shown on Figure F1. Unfortunately, the deepest sample could not be tested successfully because of severe fracturing.Previous laboratory tests of natural clay-rich sediment and shale tend to show large ranges in permeability values because of differences in the material'...

Apparent overconsolidation of mudstones in the Kumano Basin of southwest Japan: Implications for fluid pressure and fluid flow within a forearc setting

“…[32] Siliciclastic mudstones and siltstones exhibit a very wide range of permeabilities, from 10 À23 to 10 À14 m 2 [e.g., Neuzil, 1994]; that variability reflects differences in porosity, grain-size distribution, clay content, and pore-size distribution [Bennett et al, 1989;Dewhurst et al, 1998Dewhurst et al, , 1999Yang and Aplin, 2007]. The permeability values reported here are consistent with the results of Gamage et al [2011] from the Nankai Trough ( Figure 6), as well as the "global" permeability-porosity envelope established for mudstones by Neuzil [1994] (see also Dugan and Daigle [2011]; Rowe et al, [2011]; Ekinci et al, [2011];and Yue et al [2012]). The differences in permeability among our specimens are relatively small.…”

“…[] from the Nankai Trough (Figure ), as well as the “global” permeability‐porosity envelope established for mudstones by Neuzil [] (see also Dugan and Daigle []; Rowe et al ., []; Ekinci et al ., []; Saffer et al ., []; and Yue et al . []). The differences in permeability among our specimens are relatively small.…”

Evolution of sediment permeability during burial and subduction

“…; Ekinci ; Yue et al . ; Dugan & Zhao ). In these studies, vertical permeability was defined as parallel to the borehole axis, and horizontal permeability was defined as perpendicular to the borehole axis.…”

Nuclear magnetic resonance characterization of shallow marine sediments from the Nankai Trough, Integrated Ocean Drilling Program Expedition 333

“…The goals of NanTroSEIZE include understanding the link between pore pressure, rock strength, and seismicity. To achieve these goals, a large number of permeability measurements have been performed on core samples from across the Nankai accretionary complex [ Dugan and Daigle , ; Ekinci et al , ; Guo et al , ; Reuschle , ; Rowe et al , ; Saffer et al , ; Yue et al , ; Hüpers and Kopf, ; Reece et al , ; Screaton et al , ; Dugan and Zhao , ; Daigle and Dugan, ]. These measurements have provided discrete permeability values with sampling rates of ~30 m in individual boreholes that may be used to calibrate downhole NMR logs to provide continuous estimates of permeability.…”