Step 8: Slip on Two Faults and Power-law Viscoelastic Materials#
Features
Triangular cells
pylith.meshio.MeshIOPetsc
pylith.problems.TimeDependent
pylith.bc.DirichletTimeDependent
spatialdata.spatialdb.SimpleDB
spatialdata.spatialdb.ZeroDB
pylith.meshio.OutputSolnBoundary
pylith.meshio.DataWriterHDF5
Quasi-static simulation
pylith.materials.Elasticity
pylith.materials.IsotropicPowerLaw
pylith.faults.FaultCohesiveKin
pylith.faults.KinSrcStep
spatialdata.spatialdb.UniformDB
Simulation parameters#
In this example we replace the linear, isotropic Maxwell viscoelastic bulk rheology in the slab in Step 7 with an isotropic powerlaw viscoelastic rheology.
The other parameters remain the same as those in Step 6.
The parameters specific to this example are in step08_twofaults_powerlaw.cfg
.
[pylithapp.problem.materials]
slab.bulk_rheology = pylith.materials.IsotropicPowerLaw
[pylithapp.problem.materials.slab]
db_auxiliary_field = spatialdata.spatialdb.SimpleDB
db_auxiliary_field.description = Maxwell viscoelastic properties
db_auxiliary_field.iohandler.filename = mat_powerlaw.spatialdb
bulk_rheology.auxiliary_subfields.power_law_reference_strain_rate.basis_order = 0
bulk_rheology.auxiliary_subfields.power_law_reference_stress.basis_order = 0
bulk_rheology.auxiliary_subfields.power_law_exponent.basis_order = 0
Running the simulation#
$ pylith step08_twofaults_powerlaw.cfg
# The output should look something like the following.
>> /software/unix/py39-venv/pylith-debug/lib/python3.9/site-packages/pylith/meshio/MeshIOObj.py:44:read
-- meshiopetsc(info)
-- Reading finite-element mesh
>> /src/cig/pylith/libsrc/pylith/meshio/MeshIO.cc:94:void pylith::meshio::MeshIO::read(pylith::topology::Mesh*)
-- meshiopetsc(info)
-- Component 'reader': Domain bounding box:
(-100000, 100000)
(-100000, 0)
# -- many lines omitted --
25 TS dt 0.2 time 4.8
0 SNES Function norm 5.602869611772e-06
Linear solve converged due to CONVERGED_ATOL iterations 262
1 SNES Function norm 6.656502817834e-08
Linear solve converged due to CONVERGED_ATOL iterations 117
2 SNES Function norm 9.645013365143e-10
Nonlinear solve converged due to CONVERGED_FNORM_ABS iterations 2
26 TS dt 0.2 time 5.
>> /software/baagaard/py38-venv/pylith-debug/lib/python3.8/site-packages/pylith/problems/Problem.py:201:finalize
-- timedependent(info)
-- Finalizing problem.
As in Step 7, the simulation advances 26 time steps. With a nonlinear bulk rheology, the nonlinear solver now requires several iterations to converge at each time step.
Visualizing the results#
The output
directory contains the simulation output.
Each “observer” writes its own set of files, so the solution over the domain is in one set of files, the boundary condition information is in another set of files, and the material information is in yet another set of files.
The HDF5 (.h5
) files contain the mesh geometry and topology information along with the solution fields.
The Xdmf (.xmf
) files contain metadata that allow visualization tools like ParaView to know where to find the information in the HDF5 files.
To visualize the data using ParaView or Visit, load the Xdmf files.
In Fig. 84 we use ParaView to visualize the y displacement field using the viz/plot_dispwarp.py
Python script.
First, we start ParaView from the examples/reverse-2d
directory.
Before running the viz/plot_dispwarp.py
Python script as described in ParaView Python Scripts, we set the simulation name in the ParaView Python Shell.
>>> SIM = "step08_twofaults_powerlaw"
>>> FIELD_COMPONENT = "X"