A rheological model of post-seismic deformation for the 2001 Kunlun, China earthquake, Mw 7.8

The Mw7.8 Kunlun earthquake of 14 November, 2001, in the northern Tibetan Plateau of China, was the largest event inthe Chinese continental area in the latest 50 years. In this paper, layered visco-elastic models are calculated using the PSGRN/PSCMP code, and the results are fi tted to the observed...

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Detalles Bibliográficos
Autores: Chaojun Zhang, Yaolin Shi, Li Ma, Cinna Lomnitz
Tipo de recurso: artículo
Estado:Versión publicada
Fecha de publicación:2007
País:México
Institución:Universidad Nacional Autónoma de México
Repositorio:Redalyc-UNAM
OAI Identifier:oai:redalyc.org:56846301
Acceso en línea:https://www.redalyc.org/articulo.oa?id=56846301
Access Level:acceso abierto
Palabra clave:Ciencias de la Tierra
Post
rheology
viscosity
Kunlun earthquake
seismic deformation
Descripción
Sumario:The Mw7.8 Kunlun earthquake of 14 November, 2001, in the northern Tibetan Plateau of China, was the largest event inthe Chinese continental area in the latest 50 years. In this paper, layered visco-elastic models are calculated using the PSGRN/PSCMP code, and the results are fi tted to the observed post-seismic deformation. We show that a model of a surface anelasticlayer of 10km thickness over an elastic lower crust cannot explain the observed amplitude of deformation. A relaxation modelfeaturing 30km of elastic upper crust over 40km of a ductile lower crust will account for the main features of exponentialattenuation of post-seismic deformation. Combination of the two models, however, provides an even better fi t including the factthat the deformation rate was higher in the fi rst few weeks and slower thereafter. The viscous layer in the lower crust providesgood control of the post-seismic deformation, including the long term decay of deformation over a period of months. The upperanelastic layer may contribute to the observed high deformation rate in the initial few weeks after the main earthquake. Theresults suggest that rheological differences may exist between the materials on either side of the Kunlun fault.