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Table 6 Descriptions and laboratory-derived permeability data for the five fault zones defined by Wibberley and Shimamoto (2003) for the Tsukide outcrop and corresponding laboratory or hydraulic tests performed at the ITA observatory in this study

From: In-situ permeability of fault zones estimated by hydraulic tests and continuous groundwater-pressure observations

Tsukide outcrop, MTL (Wibberley and Shimamoto 2003)

ITA observatory (this study)

Zone

Distance from the central slip zone (m)

Description of fault zone and permeability structures

Laboratory-derived permeability data at confining pressure of 50 MPa (10−18 m2)

Corresponding laboratory or hydraulic tests

Permeability data (10−18 m2)

1

> 10

Relatively unfractured Ryoke mylonite of low permeability

4.5, 1.92

Drillcore Samples 1 and 2

0.31, 0.62

2

300–0

Variably fractured Ryoke mylonite and cataclasites of very heterogeneous permeability

701, 228 (fractured mylonite only)

Hydraulic tests of Hole 2

440–1500

3

0–0.1

A narrow central slip zone of extremely fine-grained fault gouge of very low permeability

54, 48.6, 299, 163

Hydraulic tests of Hole 1

53–500

4

0.1–15

A 15-m-wide zone of foliated gouge

134, 55, 20.83, 299, 4330

5

> 15

Metapelitic Sambagawa schist of moderately low permeability

187

Drillcore Samples 3 and 4

0.34, 0.37