Short-time postseismic deformation of 2001 Ms8.1 Kunlun (China) earthquake

After the Ms 8.1 Kunlun earthquake, postseismic displacements were resolved with GPS. The observed data showed that there were significant differences between the deformations on the south and the north sides of the Kunlun fault. In addition, it is shown that the direction of deformation on the north side shifted from westward to eastward after a short-time adjustment. Such GPS data are used as the constraints in finite element method (FEM) modeling of postseismic deformation. Using 3D poro-viscoelastic model, we show that the horizontal inhomogeneous viscosities in lower crust can play an important role in the geodynamic behavior. The best-fitting viscosities of lower crust are about 5.0×1017 Pa s, 9.0×1018 Pa s in Qiangtang block and Qaidam basin, respectively. The simulation suggests that the postseismic deformation of 2001 Kunlun Ms8.1 earthquake probably be caused by both the viscoelastic relaxation and poroelastic rebound. Copyright © 2009 John Wiley & Sons, Ltd.

[1]  Rongjiang Wang,et al.  PSGRN/PSCMP - a new code for calculating co- and post-seismic deformation, geoid and gravity changes based on the viscoelastic-gravitational dislocation theory , 2006, Comput. Geosci..

[2]  T. Masterlark.  Regional fault mechanics following the 1992 Landers earthquake , 2000 .

[3]  Yann Klinger,et al.  Coseismic deformation of the 2001 Mw = 7.8 Kokoxili earthquake in Tibet, measured by synthetic aperture radar interferometry , 2005 .

[4]  Chiou-Fen Shieh,et al.  Viscoelastic–afterslip concurrence: a possible mechanism in the early post-seismic deformation of the Mw 7.6, 1999 Chi-Chi (Taiwan) earthquake , 2004 .

[5]  Zheng‐Kang Shen,et al.  VISCOELASTIC TRIGGERING BETWEEN LARGE EARTHQUAKES ALONG THE EAST KUNLUN FAULT SYSTEM , 2003 .

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

[7]  Thomas J. Owens,et al.  Implications of crustal property variations for models of Tibetan plateau evolution , 1997, nature.

[8]  Kanamori,et al.  Viscoelastic flow in the lower crust after the 1992 landers, california, earthquake , 1998, Science.

[9]  Chao Ma,et al.  A Multi‐Segment Analytic Modeling of Hypocentral Geometric Characteristic Parameters of the Ms8.1 Earthquake at the Kunlun Mountains , 2006 .

[10]  F. Pollitz,et al.  Mantle Flow Beneath a Continental Strike-Slip Fault: Postseismic Deformation After the 1999 Hector Mine Earthquake , 2001, Science.

[11]  Daniel E. McNamara,et al.  Shear wave anisotropy beneath the Tibetan Plateau , 1994 .

[12]  Y. Okada.  Internal deformation due to shear and tensile faults in a half-space , 1992, Bulletin of the Seismological Society of America.

[13]  Roland Bürgmann,et al.  Evidence of power-law flow in the Mojave desert mantle , 2004, Nature.

[14]  Fred F. Pollitz,et al.  Gravitational viscoelastic postseismic relaxation on a layered spherical Earth , 1997 .

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

[16]  F. Moreau,et al.  Mechanical and electrical response due to fluid-pressure equilibration following an earthquake , 2004 .

[17]  Rongjiang Wang,et al.  Inversion for rheological parameters from post-seismic surface deformation associated with the 1960 Valdivia earthquake, Chile , 2006 .