Project Abstract
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We developed a workflow to generate high resolution, 3-D heterogeneous viscoelastic static Green's functions (GFs) for southern California. We computed displacements and stresses in response to slip on small fault patches defined by the SCEC community fault model (CFM) using the Community Velocity Model (CVM) and Community Rheology Model (CRM) as the basis for constructing the 3-D distribution of elastic and viscous properties of the crust and uppermost mantle. To date, all GF calculations have been computed using PyLith at Indiana University.
The 2019 Ridgecrest Earthquake occurred during this project, so we directed our GF efforts to this earthquake. We construct a 3D viscosity model for Southern California based on previously published 1D viscosity models. We use this 1D model as a reference viscosity model to generate a 3D viscosity model for all of southern California using seismic velocity anomaly data available from the USArray. Temperature anomalies are computed from seismic anomalies using empirical relationships and assuming an Arrhenius flow law.
We generated a suite of forward models of the Mw 7.1 Ridgecrest earthquake incorporating afterslip and viscous mantle flow to calculate postseismic surface deformation and further explore the mantle’s rheological structure. We generated a laterally heterogeneous viscosity model and create short-term effective viscosity models incorporating both Burgers rheology and power law rheology.
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