Rupture Reactivation during the 2011 Mw 9.0 Tohoku Earthquake: Dynamic Rupture and Ground‐Motion Simulations

Near‐source ground‐motion observations and kinematic source inversions suggest that the rupture process of the 2011 M w 9.0 Tohoku earthquake involved rupture reactivation, that is, repeated rupture nucleation in the same hypocentral area. This unusual phenomenon may have provided a second breath to the rupture that enhanced its final size. Here, we propose that rupture reactivation may have been governed by a slip‐weakening friction model with two sequential strength drops, the second one being activated at large slip. Such frictional behavior has been previously observed in laboratory experiments and attributed to pressurization of fault‐zone fluids by mineral decomposition reactions activated by shear heating, such as dehydration and decarbonation. Further evidence of this double‐slip‐weakening friction model is obtained here from the dynamic stress changes in the hypocentral region derived from a finite source inversion model. We incorporate this friction model in a dynamic rupture simulation comprising two main asperities constrained by source inversion models and several deep small asperities constrained by backprojection source imaging studies. Our simulation produces ground‐motion patterns along the Japanese coast consistent with observations and rupture patterns consistent with a kinematic source model featuring rupture reactivation. The deep small asperities serve as a bridge to connect the two main asperities, and the rupture reactivation mechanism is needed to reproduce the observed ground‐motion pattern. Therefore, we argue that rupture reactivation during the 2011 Tohoku earthquake is consistent with a second strength drop, possibly caused by activation of thermochemical weakening processes at large slip. Online Material: Movie of simulated rupture and wave propagation and ground velocities recorded at the KiK‐net and K‐NET seismic networks.

[1]  W. Soh,et al.  Energy taken up by co‐seismic chemical reactions during a large earthquake: An example from the 1999 Taiwan Chi‐Chi earthquake , 2009 .

[2]  Stefano Parolai,et al.  Automatic imaging of earthquake rupture processes by iterative deconvolution and stacking of high‐rate GPS and strong motion seismograms , 2014 .

[3]  Jean-Paul Ampuero,et al.  Slip-Weakening Models of the 2011 Tohoku-Oki Earthquake and Constraints on Stress Drop and Fracture Energy , 2014, Pure and Applied Geophysics.

[4]  Mizuho Ishida,et al.  Automated Seismic Moment Tensor Determination by Using On-line Broadband Seismic Waveforms , 1998 .

[5]  H. Yabuta,et al.  Investigation of the records of earthquake slip in carbonaceous materials from the Taiwan Chelungpu fault by means of infrared and Raman spectroscopies , 2015 .

[6]  Jim Mori,et al.  A review of the 2011 Tohoku-Oki earthquake (Mw 9.0): Large-scale rupture across heterogeneous plate coupling , 2013 .

[7]  D. Roten,et al.  A Rayleigh wave back‐projection method applied to the 2011 Tohoku earthquake , 2012 .

[8]  H. Aochi,et al.  Ground motions characterized by a multi-scale heterogeneous earthquake model , 2014, Earth, Planets and Space.

[9]  M. Cocco,et al.  Fault lubrication during earthquakes , 2011, Nature.

[10]  J. D. Riera,et al.  The Importance of the Dynamic Source Effects on Strong Ground Motion during the 1999 Chi-Chi, Taiwan, Earthquake: Brief Interpretation of the Damage Distribution on Buildings , 2004 .

[11]  J. Avouac,et al.  Numerical modeling of long-term earthquake sequences on the NE Japan megathrust: Comparison with observations and implications for fault friction , 2015 .

[12]  S. Aoi,et al.  Source Process of the 2011 Off the Pacific Coast of Tohoku Earthquake , 2014 .

[13]  K. Fujimoto,et al.  Earthquakes produce carbon dioxide in crustal faults , 2008 .

[14]  N. Lapusta,et al.  Stable creeping fault segments can become destructive as a result of dynamic weakening , 2013, Nature.

[15]  Gregory C. Beroza,et al.  Shallow Dynamic Overshoot and Energetic Deep Rupture in the 2011 Mw 9.0 Tohoku-Oki Earthquake , 2011, Science.

[16]  D. Garagash.  Seismic and aseismic slip pulses driven by thermal pressurization of pore fluid , 2012 .

[17]  M. Ishii.  High-frequency rupture properties of the Mw 9.0 off the Pacific coast of Tohoku Earthquake , 2011 .

[18]  H. Aochi,et al.  Conceptual multi-scale dynamic rupture model for the 2011 off the Pacific coast of Tohoku Earthquake , 2011 .

[19]  Sarah E. Minson,et al.  The 2011 Magnitude 9.0 Tohoku-Oki Earthquake: Mosaicking the Megathrust from Seconds to Centuries , 2011, Science.

[20]  Emanuele Casarotti,et al.  Forward and adjoint simulations of seismic wave propagation on fully unstructured hexahedral meshes , 2011 .

[21]  Jean-Paul Ampuero,et al.  A window into the complexity of the dynamic rupture of the 2011 Mw 9 Tohoku‐Oki earthquake , 2011 .

[22]  J. Rice.  Heating and weakening of faults during earthquake slip , 2006 .

[23]  H. Aochi,et al.  Historical seismicity and dynamic rupture process of the 2011 Tohoku-Oki earthquake , 2013 .

[24]  John B. Rundle,et al.  Geocomplexity and the Physics of Earthquakes , 2000 .

[25]  H. Ueno,et al.  Source process of the 2011 off the Pacific coast of Tohoku Earthquake with the combination of teleseismic and strong motion data , 2011 .

[26]  Nadia Lapusta,et al.  Towards inferring earthquake patterns from geodetic observations of interseismic coupling , 2010 .

[27]  M. Takeo,et al.  Determination of constitutive relations of fault slip based on seismic wave analysis , 1997 .

[28]  Y. Yagi,et al.  Smooth and rapid slip near the Japan Trench during the 2011 Tohoku-oki earthquake revealed by a hybrid back-projection method , 2012 .

[29]  Yihe Huang,et al.  A dynamic model of the frequency-dependent rupture process of the 2011 Tohoku-Oki earthquake , 2012, Earth, Planets and Space.

[30]  K. Fujimoto,et al.  Clay mineral reactions caused by frictional heating during an earthquake: An example from the Taiwan Chelungpu fault , 2008 .

[31]  Kelin Wang,et al.  The updip and downdip limits to great subduction earthquakes: Thermal and structural models of Casca , 1999 .

[32]  J. Hower,et al.  Experimental frictional heating of coal gouge at seismic slip rates: Evidence for devolatilization and thermal pressurization of gouge fluids , 2006 .

[33]  Masataka Ando,et al.  Evidence of large scale repeating slip during the 2011 Tohoku‐Oki earthquake , 2011 .

[34]  J. D. Riera,et al.  Distribution of Dynamic and Static Stress Changes during 2000 Tottori (Japan) Earthquake: Brief Interpretation of the Earthquake Sequences; Foreshocks, Mainshock and Aftershocks , 2002 .

[35]  Yuji Yagi,et al.  A unified source model for the 2011 Tohoku earthquake , 2011 .

[36]  P. Mai,et al.  The transition of dynamic rupture styles in elastic media under velocity-weakening friction , 2012 .

[37]  Y. Fukahata,et al.  A scenario for the generation process of the 2011 Tohoku earthquake based on dynamic rupture simulation: Role of stress concentration and thermal fluid pressurization , 2012, Earth, Planets and Space.

[38]  Kojiro Irikura,et al.  Surface Rupturing and Buried Dynamic-Rupture Models Calibrated with Statistical Observations of Past Earthquakes , 2008 .

[39]  J. Rice,et al.  Earthquake ruptures with thermal weakening and the operation of major faults at low overall stress levels , 2009 .

[40]  J. D. Platt,et al.  Steadily propagating slip pulses driven by thermal decomposition , 2015 .

[41]  N. Hirata,et al.  A complex rupture image of the 2011 off the Pacific coast of Tohoku Earthquake revealed by the MeSO-net , 2011 .

[43]  Jean Sulem,et al.  Thermal decomposition of carbonates in fault zones: Slip-weakening and temperature-limiting effects , 2009 .

[44]  Robert W. Graves,et al.  Sources of shaking and flooding during the Tohoku-Oki earthquake: A mixture of rupture styles , 2012 .

[45]  Luis A. Dalguer,et al.  Numerical Study of Ground-Motion Differences between Buried-Rupturing and Surface-Rupturing Earthquakes , 2009 .

[46]  Luis A. Dalguer,et al.  Dynamic earthquake rupture modelled with an unstructured 3-D spectral element method applied to the 2011 M9 Tohoku earthquake , 2014 .

[47]  Shuo Ma,et al.  Dynamic wedge failure reveals anomalous energy radiation of shallow subduction earthquakes , 2013 .

[49]  J. Rice,et al.  of Geophysical Research : Solid Earth Strain localization driven by thermal decomposition during seismic shear , 2015 .

[50]  Haruko Sekiguchi,et al.  Rupture process of the 2011 Tohoku‐Oki mega‐thrust earthquake (M9.0) inverted from strong‐motion data , 2011 .

[51]  D. J. Andrews,et al.  Rupture velocity of plane strain shear cracks , 1976 .

[52]  Michel Bouchon,et al.  The state of stress on some faults of the San Andreas system as inferred from near-field strong motion data , 1997 .

[53]  H. Kanamori,et al.  Microscopic and Macroscopic Physics of Earthquakes , 2013 .

[54]  Jin-Han Ree,et al.  Ultralow Friction of Carbonate Faults Caused by Thermal Decomposition , 2007, Science.

[55]  Jeremy E. Kozdon,et al.  Rupture to the Trench: Dynamic Rupture Simulations of the 11 March 2011 Tohoku Earthquake , 2013 .

[56]  Thorne Lay,et al.  Inversion of high‐rate (1 sps) GPS data for rupture process of the 11 March 2011 Tohoku earthquake (Mw 9.1) , 2011 .

[57]  Chris Marone,et al.  The depth of seismic faulting and the upper transition from stable to unstable slip regimes , 1988 .

[58]  K. Hirahara,et al.  Megaquake cycle at the Tohoku subduction zone with thermal fluid pressurization near the surface , 2012 .

[59]  J. Sarout,et al.  Thermochemical pressurization of faults during coseismic slip , 2010 .

[60]  Yuji Yagi,et al.  Rupture process of the 2011 Tohoku‐oki earthquake and absolute elastic strain release , 2011 .