Frictional properties of fault zone gouges from the J-FAST drilling project (M sub(w) 9.0 2011 Tohoku-Oki earthquake)

Smectite-rich fault gouges recovered during Integrated Ocean Drilling Program Expedition 343 (Japan Trench Fast Drilling Project (J-FAST)) from the plate boundary slip zone of the 2011 M sub(w) 9.0 Tohoku-Oki earthquake were deformed at slip velocities of 10 mu ms super(-1) to 3.5ms super(-1) and no...

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Bibliographic Details
Published in:Geophysical research letters 2015-04, Vol.42 (8), p.2691-2699
Main Authors: Remitti, F, Smith, SAF, Mittempergher, S, Gualtieri, A F, Di Toro, G
Format: Article
Language:English
Subjects:
Drilling
Friction
Rupture
Seismic phenomena
Slip
Slip velocity
Strengthening
Trenches
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Summary:Smectite-rich fault gouges recovered during Integrated Ocean Drilling Program Expedition 343 (Japan Trench Fast Drilling Project (J-FAST)) from the plate boundary slip zone of the 2011 M sub(w) 9.0 Tohoku-Oki earthquake were deformed at slip velocities of 10 mu ms super(-1) to 3.5ms super(-1) and normal stresses up to 12MPa. Water-dampened gouges (1) are weaker (apparent friction coefficient, mu * 0.1ms super(-1)). A significant amount of amorphous material formed in room-humidity experiments at low- and high-slip velocities, likely by comminution and disordering of smectite. Our results indicate that the frictional properties of water-dampened gouges could have facilitated propagation of the Tohoku-oki rupture to the trench and large coseismic slip at shallow depths. Key Points * Strengthening at intermediate velocities in room-humidity Tohoku-oki gouge * Lack of strengthening in water-dampened gouges facilitated rupture to the trench * Amorphization of clays in room-humidity gouge at all tested slip velocities
ISSN:0094-8276
1944-8007
DOI:10.1002/2015GL063507