Poster #103, Tectonic Geodesy
Power-law viscoelastic flow of the lower Makran accretionary prism following the 2013 Baluchistan earthquake
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Poster Presentation
2021 SCEC Annual Meeting, Poster #103, SCEC Contribution #11400 VIEW PDF
ewing geometries to construct 7-year surface displacement timeseries following the earthquake. We constructed a 3-D finite element model of the Makran accretionary prism with the Hoshab fault plane hosting the 2013 Baluchistan earthquake. We used open-source FEM software PyLith to assign material properties to five different domains of the model. We varied the three main parameters controlling the viscoelastic properties of the lower prism (i.e. power-law exponent n, activation enthalpy Q, and pre-exponential constant A) while keeping the properties of other domains constant. We prescribed co-seismic slip distribution on the Hoshab fault and simulated the post-seismic viscoelastic deformation for 10 years. We compared the ~6000 forward-modeled post-seismic deformation timeseries to the observed InSAR timeseries and our results suggest that: 1. Viscoelastic relaxation alone of the Makran lower prism (8-40 km depth) explains most of the post-seismic surface deformation, and 2. viscoelastic relaxation requires power-law relaxation with parameters ranges of n = 3-4, Q = 100-140 kJ·mol^-1, and A = 10^-3-10^3 MPa^-n·s^-1. These results are consistent with post-seismic-triggered permanent deformation of the prism dominated by dislocation creep of quartz-rich materials under saturated condition.
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