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

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doi: 10.1002/2015GL063507
Author(s): Remitti, Francesca; Smith, S. A. F.; Mittempergher, S.; Gualtieri, A. F.; Di Toro, G.
Author Affiliation(s): Primary:
Universita di Modena e Reggio Emilia, Dipartimento di Scienze Chimiche e Geologiche, Modena, Italy
University of Otago, New Zealand
University of Manchester, United Kingdom
Volume Title: Geophysical Research Letters
Source: Geophysical Research Letters, 42(8), p.2691-2699. Publisher: American Geophysical Union, Washington, DC, United States. ISSN: 0094-8276 CODEN: GPRLAJ
Note: In English. 36 refs.; illus., incl. 1 table
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 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) than room-humidity gouges (apparent friction coefficient, µ* ∼0.1-0.35) at all slip velocities, (2) are velocity insensitive to velocity weakening at all slip velocities, unlike room-humidity gouges that are velocity strengthening at intermediate velocities (V = 0.001-0.1 m s-1), and (3) have negligible peak µ* at high slip velocities (V>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. Abstract Copyright (2015). American Geophysical Union. All Rights Reserved.
Year of Publication: 2015
Research Program: IODP Integrated Ocean Drilling Program
Key Words: 16 Structural Geology; 19 Geophysics, Seismology; Asia; Drilling; Earthquakes; Expedition 343; Expeditions 343/343T; Far East; Fault zones; Faults; Gouge; Great earthquakes; Honshu; Integrated Ocean Drilling Program; Japan; Japan Trench; Japan Trench Fast Drilling Project; Magnitude; North Pacific; Northwest Pacific; Pacific Ocean; Tohoku-Oki earthquake 2011; West Pacific
Coordinates: N375619 N375620 E1435449 E1435447
Record ID: 2017014839
Copyright Information: GeoRef, Copyright 2017 American Geosciences Institute. Reference includes data from John Wiley & Sons, Chichester, United Kingdom