Postseismic deformation after 2008 Wenchuan Earthquake. Issue 339 (November 2014)

• Record Type: Journal Article
• Authors: Xu, C. J.; Fan, Q. B.; Wang, Q.; Yang, S. M.; Jiang, G. Y.
• Is Part Of: Survey review. Volume 46:Issue 339(2014:Nov.)
• Page Start: 432
• Page End: 436
• Publication Date: 2014-11
• Subjects: Wenchuan Earthquake, -- Postseismic deformation, -- Afterslip, -- Viscoelastic relaxation; Surveying -- Periodicals; Great Britain -- Surveys -- Periodicals; 526.9
• DOI: 10.1179/1752270614Y.0000000128
• Languages: English
• ISSNs: 0039-6265

Abstract

Abstract : Apparent postseismic deformation was observed after the 2008 Wenchuan earthquake, China. The displacement in the direction normal to the fault decays to nearly zero after 2013, but the significant dextral movement did not decay obviously during our observation of up to May 2013. It indicates that the stress paralleled to the fault in the southern part of the rupture zone was not relaxed during the coseismic slip. The unrelaxed stress transfers northward after the earthquake and continues after 2013. The postseismic deformation may be dominated by afterslip or stress readjustment, but the effects of the viscoelastic relaxation also cannot be ignored. The low velocity zone under the Bayan Har block, which is velocity strengthening, may greatly affect the postseismic deformation and makes it possible that the lower crust ductile flow and the shortening of the crust both contribute to the uplift of the Longmen Shan. The viscoelastic coefficients of the low velocity zone and the lower crust should be larger than 3×10 18 Pa.s which is optimised with our observations by using the single viscoelastic relaxation model.