What Caused the 2011 Tohoku-Oki Earthquake? : Effects of Dynamic Weakening
Bunichiro Shibazaki* and Hiroyuki Noda**
*International Institute of Seismology and Earthquake Engineering, Building Research Institute, 1 Tatehara, Tsukuba, Ibaraki 305-0802, Japan
**Department of Mathematical Science and Advanced Technology, Japan Agency for Marine-Earth Science and Technology, 3173-25 Showa-machi, Kanazawa-ku, Yokohama, Kanagawa 236-0001, Japan
Some observational studies have suggested that the 2011 great Tohoku-Oki earthquake (Mw9.0) released a large portion of the accumulated elastic strain on the plate interface owing to considerable weakening of the fault. Recent experimental and theoretical studies have shown that considerable dynamic weakening can occur at high slip velocities because of thermal pressurization or thermal weakening processes. This paper reviews severalmodels of the generation of megathrust earthquakes along the Japan Trench subduction zone, that considers thermal pressurization or a friction law that exhibits velocity weakening at high slip velocities, and it discusses the causes of megathrust earthquakes. To reproduce megathrust earthquakes with recurrence intervals of several hundreds of years, it will be necessary to consider the existence of a region at the shallow subduction plate boundary where significant dynamic weakening occurs due to thermal pressurization or other thermal weakening processes.
-  Y. Fujii, K. Satake, S. Sakai, M. Shinohara, and T. Kanazawa, “Tsunami source of the 2011 off the Pacific coast of Tohoku earthquake,” Earth Planets Space, Vol.63, pp. 815-820, 2011.  S. Ide, A. Baltay, and G. C. Beroza, “Shallow dynamic overshoot and energetic deep rupture in the 2011 Mw9.0 Tohoku-Oki earthquake,” Science, Vol.332, pp. 1426-1429, doi:10.1126/science.1207020, 2011. Y. Ito, T. Tsuji, Y. Osada, M. Kido, D. Inazu, Y. Hayashi, H. Tsushima, R. Hino, and H. Fujimoto, “Frontal wedge deformation near the source region of the 2011 Tohoku-Oki earthquake,” Geophys. Res. Lett., Vol.38, L00G05, doi:10.1029/2011GL048355, 2011. T. Lay, C. J. Ammon, H. Kanamori, L. Xue, and M. J. Kim, “Possible large near trench slip during the 2011 Mw9.0 the Pacific coast of Tohoku Earthquake,” Earth Planets Space, Vol.63, pp. 687-692, doi:10.5047/eps.2011.05.033, 2011. Y. Yagi and Y. Fukahata, “Rupture process of the 2011 Tohoku-oki earthquake and absolute elastic strain release,” Geophys. Res. Lett., Vol.38, L19307, doi:10.1029/2011GL048701, 2011. Y. Yokota, K. Koketsu, Y. Fujii, K. Satake, S. Sakai, M. Shinohara, and T. Kanazawa, “Joint inversion of strong motion, teleseismic, geodetic, and tsunami datasets for the rupture process of the 2011 Tohoku earthquake,” Geophys. Res. Lett., Vol.38, L00G21, doi:10.1029/2011GL050098, 2011. S. Ozawa, T. Nishimura, H. Munekane, H. Suito, T. Kobayashi, M. Tobita, and T. Imakiire, “Preceding, coseismic, and postseismic slips of the 2011 Tohoku earthquake,” Japan, J. Geophys. Res., Vol.117, B07404, doi:10.1029/2011JB009120, 2012. T. Iinuma et al., “Coseismic slip distribution of the 2011 off the Pacific Coast of Tohoku Earthquake (M9.0) refined by means of seafloor geodetic data,” J. Geophys. Res., Vol.117, B07409, doi:10.1029/2012JB009186, 2012a. A. Hasegawa, K. Yoshida, and T. Okada, “Nearly complete stress drop in the 2011 Mw9.0 off the Pacific coast of Tohoku Earthquake,” Earth Planets Space, Vol.63, pp. 703-707, 2011. Y. Fukahata, Y. Yagi, and Y. Mitsui, “Absolute strain release in the 2011 Tohoku-oki Earthquake: Waveform inversion and dynamic fault weakening,” Jour. Geol. Soc. Japan, Vol.118, pp. 396-409, 2012. Y. Yamanaka and M. Kikuchi, “Asperity map along the subduction zone in northeastern Japan inferred from regional seismic data,” J. Geophys. Res., Vol.109, B07307, doi:10.1029/2003JB002683, 2004. K. Satake, Y. Namegaya, and S. Yamamoto, “Numerical simulation of the AD 869 Jogan tsunami in Ishinomaki and Sendai plains,” Annual Report of Active Fault and Paleoearthquake Research, Vol.8, pp. 71-89, 2008. N. Kato and S. Yoshida, “A shallow strong patch model for the 2011 great Tohoku-oki earthquake: A numerical simulation,” Geophys. Res. Lett., Vol.38, L00G04, doi:10.1029/2011GL048565, 2011. S. Yoshida and N. Kato, “Pore pressure distribution along plate interface that causes a shallow asperity of the 2011 great Tohoku-oki earthquake,” Geophys. Res. Lett., Vol.38, L00G13, doi:10.1029/2011GL048902, 2011. T. Hori and S. Miyazaki, “A possible mechanism of M9 earthquake generation cycles in the area of repeating M7 and 8 earthquakes surrounded by aseismic sliding,” Earth Planets Space, Vol.63, pp. 773-777, 2011. M. Ohtani, K. Hirahara, T. Hori, and M. Hyodo, “Comparative study on quasi-dynamic earthquake cycle models for the 2011 giant Tohoku earthquake,” 2011 AGU Fall Meeting, Abstract U51B-0044, 2011. H. Noda and N. Lapusta, “Three-dimensional earthquake sequence simulations with evolving temperature and pore pressure due to shear heating: Effect of heterogeneous hydraulic diffusivity,” J. Geophys. Res., Vol.115, B12314, doi:10.1029/2010JB007780, 2010. H. Noda and N. Lapusta, “3D simulations of seismic and aseismic fault slip with evolving temperature and pore pressure: Interaction of two fault segments and low interseismic shear stress,” Eos Trans. AGU, Vol.90, No.52, Fall Meet. Suppl., Abstract T51E-02, 2009. H. Noda and N. Lapusta, “Stable creeping fault segments can become destructive as a result of dynamic weakening,” Nature, Vol.493, pp. 518-521, doi:10.1038/nature11703, 2013. Y. Mitsui, N. Kato, Y. Fukahata, and K. Hirahara, “Megaquake cycle at the Tohoku subduction zone with thermal fluid pressurization near the surface,” Earth Planet. Sci. Lett., Vol.325-326, pp. 21-26, doi:10.1016/j.epsl.2012.01.026, 2012. G. Di Toro, R. Han, T. Hirose, N. De Paola, S. Nielsen, K. Mizoguchi, F. Ferri, M. Cocco, and T. Shimamoto, “Fault lubrication during earthquakes,” Nature, Vol.471, pp. 494-498, 2011. A. Tsutsumi, O. Fabbri, A. M. Karpoff, K. Ujiie, and A. Tsujimoto, “Friction velocity dependence of clay-rich fault material along a megasplay fault in the Nankai subduction zone at intermediate to high velocities,” Geophys. Res. Lett., Vol.38, L19301, doi:10.1029/2011GL049314, 2011. K. Ujiie and A. Tsutsumi, “High-velocity frictional properties of clay-rich fault gouge in a megasplay fault zone, Nankai subduction zone,” Geophys. Res. Lett., Vol.37, L24310, doi:10.1029/2010GL046002, 2010. D. R. Faulkner, T. M. Mitchell, J. Behnsen, T. Hirose, and T. Shimamoto, “Stuck in the mud? Earthquake nucleation and propagation through accretionary forearcs,” Geophys. Res. Lett., Vol.38, L18303, doi:10.1029/2011GL048552, 2011. B. Shibazaki, T. Matsuzawa, A. Tsutsumi, K. Ujiie, A. Hasegawa, and Y. Ito, “3D modeling of the cycle of a great Tohoku-oki earthquake, considering frictional behavior at low to high slip velocities,” Geophys. Res. Lett., Vol.38, L21305, doi:10.1029/2011GL049308, 2011. B. Shibazaki, H. Noda, T. Shimamoto, and T. Hori, “3D modeling of the cycle of a great Tohoku-oki earthquake considering thermal pressurization,” Japan Geoscience Union Meeting, SSS29-P04, 2012. F. M. Chester, C. Rowe, K. Ujiie, J. Kirkpatrick, C. Regalla, F. Remitti, J. C. Moore, V. Toy, M. Wolfson-Schwehr, S. Bose, J. Mori, J. J. Kameda, E. E. Brodsky, N. Eguchi, S. Toczko, and Expedition 343 and 343T Scientists, “Structure and composition of the plateboundary slip zone for the 2011 Tohoku-oki earthquake,” Science, Vol.342, pp. 1208-1211, doi:10.1126/science.1243719, 2013. K. Ujiie, H. Tanaka, T. Saito, A. Tsutsumi, J. J. Mori, J. Kameda, E. E. Brodsky, F. M. Chester, N. Eguchi, S. Toczko, and Expedition 343 and 343T Scientists, “Low coseismic shear stress on the Tohoku-oki megathrust determined from laboratory experiments,” Science, Vol.342, pp. 1211-1214, doi:10.1126/science.1243485, 2013. P. M. Fulton, E. E. Brodsky, Y. Kano, J. Mori, F. Chester, T. Ishikawa, R. N. Harris, W. Lin, N. Eguchi, S. Toczko, and Expedition 343, 343T, and KR13-08 Scientists, “Low coseismic friction on the Tohoku-oki fault determined from temperature measurements,” Science, Vol.342, pp. 1214-1217, doi:10.1126/science.1243641, 2013. J. H. Dieterich, “Constitutive properties of rock with simulated gouge,” in Mechanical Behavior of Crustal Rocks, pp. 108-120, Geophys. Monogr. Ser, 24, 1981. A. H. Lachenbruch, “Frictional heating, fluid pressure, and the resistance to fault motion,” J. Geophys. Res., Vol.85, pp. 6097-6112, 1980. W. Tanikawa and T. Shimamoto, “Frictional and transport properties of the Chelungpu fault from shallow borehole data and their correlation with seismic behavior during the 1999 Chi-Chi earthquake,” J. Geophys. Res., Vol.114, B01402, doi:10.1029/2008JB005750, 2009. Y. Mitsui, Y. Iio, and Y. Fukahata, “A scenario for the generation process of the 2011 Tohoku earthquake based on dynamic rupture simulation: role of stress concentration and thermal fluid,” Earth Planets Space, Vol.64, pp. 1177-1187, 2012. W. Tanikawa, T. Hirose, H. Mukoyoshi, O. Tadai, and W. Lin, “Fluid transport properties in sediments and their role in large slip near the surface of the plate boundary fault in the Japan Trench,” Earth and Planetary Science Letters, Vol.382, pp. 150-160. dx.doi.org/10.1016/j.epsl.2013.08.052, 2013. N. Beeler, “Constructing constitutive relationships for seismic and aseismic fault slip,” Pure Appl. Geophys., Vol.166, pp. 1775-1798, 2009. E. M. Dunham, D. Belanger, L. Cong, and J. E. Kozdon, “Earthquake ruptures with strongly rate-weakening friction and off-fault plasticity: 1. Planar faults,” Bull. Seismol. Soc. Am., Vol.101, pp. 2296-2307; doi:10.1785/0120100075, 2011. J. R. Rice, “Spatio-temporal complexity of slip on a fault,” J. Geophys. Res., Vol.98, pp. 9885-9907, 1993. W. D. Stuart, T. Hildenbrand, and R. Simpson, “Stressing of the New Madrid Seismic Zone by a lower crust detachment fault,” J. Geophys. Res., Vol.102, pp. 27623-27633., 1997. W. H. Press, S. A. Teukolsky, W. T. Vetterling, and B. P. Flannery, “Numerical recipes in Fortran: the art of scientific computing, second edition,” Cambridge University Press, New York, 1992.  Y. Yamanaka and M. Kikuchi, “Oct. 31, Fukushima-oki earthquake (Mj = 6.8),” EIC Seismological Notes, Vol.135, 2003 (in Japanese),
http://www.eri.u-tokyo.ac.jp/sanchu/Seismo_Note/EIC_News/031031.html [accessed Jan. 17, 2014] S. Murotani, “Rupture processes of large Fukushima-oki Earthquakes in 1938,” Master’s thesis, The University of Tokyo, 2003. K. Satake, Y. Fujii, T. Harada, and Y. Namegaya, “Time and space distribution of coseismic slip of the 2011 Tohoku earthquake as inferred from tsunami waveform data,” Bull. Seismol. Soc. Am., Vol.103, pp. 1473-1492, doi:10.1785/0120120122, 2013. A. M. Rubin and J.-P. Ampuero, “Earthquake nucleation on (aging) rate and state faults,” J. Geophys. Res., Vol.110, B11312, doi:10.1029/2005JB003686, 2005. J. L. Hardebeck, “Coseismic and postseismic stress rotations due to great subduction zone earthquakes,” Geophys. Res. Lett., Vol.39, L21313, doi:10.1029/2012GL053438, 2012.