As mentioned in the PyLith manual, the files associated with SCEC spontaneous dynamic rupture benchmarks are in the https://github.com/geodynamics/pylith_benchmarks repository. This large benchmark suite was created over about 10 years. As a result, many of the input files have not been updated to the current version of PyLith. Additionally, you will need CUBIT/Trelis to generate the finite-element meshes.
You will likely need to update the parameter files for the current version of PyLith. See the CHANGES file in the top-level source directory of PyLith for a list of changes for each release. If you update the parameter files for any of the benchmarks, please submit a pull request.