Frictional properties of fault zone gouges from the J-FAST drilling project (Mw 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 Mw 9.0 Tohoku‐Oki earthquake were deformed at slip velocities of 10 µm s−1 to 3.5 m s−1 and normal stresses up to 1...
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Veröffentlicht in: | Geophysical research letters 2015-04, Vol.42 (8), p.2691-2699 |
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Sprache: | eng |
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Zusammenfassung: | 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 Mw 9.0 Tohoku‐Oki earthquake were deformed at slip velocities of 10 µm s−1 to 3.5 m s−1 and normal stresses up to 12 MPa. Water‐dampened gouges (1) are weaker (apparent friction coefficient, μ* 0.1 m s−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 |
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ISSN: | 0094-8276 1944-8007 |
DOI: | 10.1002/2015GL063507 |