Contributions of poroelastic rebound and a weak volcanic arc to the postseismic deformation of the 2011 Tohoku earthquake

A better understanding of fluid-related processes such as poroelastic rebound of the upper crust and weakening of the lower crust beneath the volcanic arc helps better understand and correctly interpret the heterogeneity of postseismic deformation following great subduction zone earthquakes. The postseismic deformation following the 2011 Mw9.0 Tohoku earthquake, recorded with unprecedented high resolution in space and time, provides a unique opportunity to study these ‘second-order’ subduction zone processes. We use a three-dimensional viscoelastic finite element model to study the effects of fluid-related processes on the postseismic deformation. A poroelastic rebound (PE) model alone with fluid flow in response to coseismic pressure changes down to 6 and 16 km in the continental and oceanic crusts, respectively, predicts 0 to 6 cm uplift on land, up to approximately 20 cm uplift above the peak rupture area, and up to approximately 15 cm subsidence elsewhere offshore. PE produces up to approximately 30 cm of horizontal motions in the rupture area but less than 2 cm horizontal displacements on land. Effects of a weak zone beneath the arc depend on its plan-view width and vertical viscosity profile. Our preferred model of the weak sub-arc zone indicates that in the first 2 years after the 2011 earthquake, the weak zone contributes to the surface deformation on land on the order of up to 20 cm in both horizontal and vertical directions. The weak-zone model helps eliminate the remaining systematic misfit of the viscoelastic model of upper mantle relaxation and afterslip of the megathrust.

[1]  J. Rice,et al.  Some basic stress diffusion solutions for fluid‐saturated elastic porous media with compressible constituents , 1976 .

[2]  Arthur Raefsky,et al.  A simple and efficient method for introducing faults into finite element computations , 1981 .

[3]  J. C. Savage.  A dislocation model of strain accumulation and release at a subduction zone , 1983 .

[4]  The nonclassical entropy flux in extended thermodynamics , 1992 .

[5]  R. Martin,et al.  The role of fluids in crustal processes , 1992 .

[6]  X. Pichon,et al.  Accretion and Erosion in Subduction Zones: The Role of Fluids , 1993 .

[7]  Paul Rosen,et al.  Postseismic Rebound in Fault Step-Overs Caused by Pore Fluid Flow , 1996, Science.

[8]  E. Engdahl,et al.  Global teleseismic earthquake relocation with improved travel times and procedures for depth determination , 1998, Bulletin of the Seismological Society of America.

[9]  Kenneth W. Hudnut,et al.  Poroelastic rebound along the Landers 1992 earthquake surface rupture , 1998 .

[10]  S. Ingebritsen,et al.  Permeability of the continental crust: Implications of geothermal data and metamorphic systems , 1999 .

[11]  B. Bekins,et al.  Fluid budgets at convergent plate margins: Implications for the extent and duration of fault-zone dilation , 1999 .

[12]  Timothy H. Dixon,et al.  REVEL: A model for Recent plate velocities from space geodesy , 2002 .

[13]  S. Peacock,et al.  High‐resolution models of subduction zones: Implications for mineral dehydration reactions and the transport of water into the deep mantle , 2002 .

[14]  Paul Segall,et al.  Post-earthquake ground movements correlated to pore-pressure transients , 2003, Nature.

[15]  P. Bird.  An updated digital model of plate boundaries , 2003 .

[16]  T. Masterlark.  Finite element model predictions of static deformation from dislocation sources in a subduction zone: Sensitivities to homogeneous, isotropic, Poisson-solid, and half-space assumptions , 2003 .

[17]  Hans-Joachim Kümpel,et al.  Poroelasticity: Efficient modeling of strongly coupled, slow deformation processes in a multilayered half-space , 2003 .

[18]  Takeshi Sagiya,et al.  A revised dislocation model of interseismic deformation of the Cascadia subduction zone , 2003 .

[19]  Kelin Wang,et al.  Three-dimensional viscoelastic finite element model for postseismic deformation of the great 1960 Chile earthquake , 2004 .

[20]  Yuri Fialko,et al.  Evidence of fluid-filled upper crust from observations of postseismic deformation due to the 1992 Mw7.3 Landers earthquake , 2004 .

[21]  C. Manning.  The chemistry of subduction-zone fluids , 2004 .

[22]  J. Nakajima,et al.  Anomalous low‐velocity zone and linear alignment of seismicity along it in the subducted Pacific slab beneath Kanto, Japan: Reactivation of subducted fracture zone? , 2006 .

[23]  Robert W. King,et al.  Independent active microplate tectonics of northeast Asia from GPS velocities and block modeling , 2006 .

[24]  M. Bevis,et al.  Crustal motion in the zone of the 1960 Chile earthquake: Detangling earthquake‐cycle deformation and forearc‐sliver translation , 2007 .

[25]  K. Heki,et al.  Slow postseismic recovery of geoid depression formed by the 2004 Sumatra‐Andaman Earthquake by mantle water diffusion , 2007 .

[26]  M. Manga,et al.  Thermal demagnetization of Martian upper crust by magma intrusion , 2007 .

[27]  F. Pollitz,et al.  Effect of 3-D viscoelastic structure on post-seismic relaxation from the 2004 M= 9.2 Sumatra earthquake , 2008 .

[28]  Georg Dresen,et al.  Rheology of the Lower Crust and Upper Mantle: Evidence from Rock Mechanics, Geodesy, and Field Observations , 2008 .

[29]  T. Masterlark,et al.  Next generation of deformation models for the 2004 M9 Sumatra‐Andaman earthquake , 2008 .

[30]  Kelin Wang,et al.  Coseismic strengthening of the shallow portion of the subduction fault and its effects on wedge taper , 2008 .

[31]  K. Lambeck,et al.  Holocene relative sea-level changes and vertical movements along the Italian and Istrian coastlines , 2009 .

[32]  N. Umino,et al.  Mapping the mantle wedge and interplate thrust zone of the northeast Japan arc , 2009 .

[33]  Jeffrey T. Freymueller,et al.  A viscoelastic and afterslip postseismic deformation model for the 1964 Alaska earthquake , 2009 .

[34]  J. Nakajima,et al.  Anomalous deepening of a seismic belt in the upper-plane of the double seismic zone in the Pacific slab beneath the Hokkaido corner: Possible evidence for thermal shielding caused by subducted forearc crust materials , 2010 .

[35]  Walter D. Mooney,et al.  Poroelastic stress-triggering of the 2005 M8.7 Nias earthquake by the 2004 M9.2 Sumatra–Andaman earthquake , 2010 .

[36]  Z. Altamimi,et al.  ITRF2008: an improved solution of the international terrestrial reference frame , 2011 .

[37]  Fred F. Pollitz,et al.  Geodetic slip model of the 2011 M9.0 Tohoku earthquake , 2011 .

[38]  G. Hayes.  Rapid source characterization of the 2011 Mw 9.0 off the Pacific coast of Tohoku Earthquake , 2011 .

[39]  J. Urrutia‐Fucugauchi,et al.  Overview of Recent Coastal Tectonic Deformation in the Mexican Subduction Zone , 2011 .

[40]  J. Muto.  Rheological structure of northeastern Japan lithosphere based on geophysical observations and rock mechanics , 2011 .

[41]  T. Iinuma,et al.  Coseismic slip distribution of the 2011 off the Pacific coast of Tohoku Earthquake (M 9.0) estimated based on GPS data—Was the asperity in Miyagi-oki ruptured? , 2011 .

[42]  P. Segall,et al.  Challenging the rate‐state asperity model: Afterslip following the 2011 M9 Tohoku‐oki, Japan, earthquake , 2012 .

[43]  Kelin Wang,et al.  Deformation cycles of subduction earthquakes in a viscoelastic Earth , 2012, Nature.

[44]  Motoyuki Kido,et al.  Coseismic slip distribution of the 2011 off the Pacific Coast of Tohoku Earthquake (M9.0) refined by means of seafloor geodetic data , 2012 .

[45]  J. Muto,et al.  Geodetic evidence of viscoelastic relaxation after the 2008 Iwate-Miyagi Nairiku earthquake , 2012, Earth, Planets and Space.

[46]  Kelin Wang,et al.  Spherical‐Earth finite element model of short‐term postseismic deformation following the 2004 Sumatra earthquake , 2012 .

[47]  T. Iinuma,et al.  Strain anomalies induced by the 2011 Tohoku Earthquake (Mw 9.0) as observed by a dense GPS network in northeastern Japan , 2012, Earth, Planets and Space.

[48]  Tomokazu Kobayashi,et al.  Preceding, coseismic, and postseismic slips of the 2011 Tohoku earthquake, Japan , 2012 .

[49]  Robert W. King,et al.  Active tectonics of northwestern U.S. inferred from GPS‐derived surface velocities , 2013 .

[50]  T. Matsuzawa,et al.  Pre- and postseismic slow slip surrounding the 2011 Tohoku-oki earthquake rupture , 2013 .

[51]  Michael Bevis,et al.  Coseismic and postseismic slip associated with the 2010 Maule Earthquake, Chile: Characterizing the Arauco Peninsula barrier effect , 2013 .

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

[53]  Y. Kuwahara,et al.  Constraints on the three-dimensional thermal structure of the lower crust in the Japanese Islands , 2013, Earth, Planets and Space.

[54]  T. Okada,et al.  Two‐dimensional viscosity structure of the northeastern Japan islands arc‐trench system , 2013 .

[55]  M. Fujita,et al.  Interplate coupling off northeastern Japan before the 2011 Tohoku‐oki earthquake, inferred from seafloor geodetic data , 2013 .

[56]  P. Segall,et al.  A decadal‐scale deformation transient prior to the 2011 Mw 9.0 Tohoku‐oki earthquake , 2014 .

[57]  Thomas R. Walter,et al.  Overlapping post-seismic deformation processes: afterslip and viscoelastic relaxation following the 2011 Mw 9.0 Tohoku (Japan) earthquake , 2014 .

[58]  M. Fujita,et al.  Evidence of viscoelastic deformation following the 2011 Tohoku‐Oki earthquake revealed from seafloor geodetic observation , 2014 .