Third Uniform California Earthquake Rupture Forecast (UCERF3) Fault System Solutions

Data files for the Third Uniform California Earthquake Rupture Forecast (UCERF3), as described in https://doi.org/10.1785/0120130164.

These data are stored in the original UCERF3 Fault System Solution file format, which uses binary files within zip containers. This format is being revised, and updates to this dataset will be published when the new and more user friendly format is finalized. See https://opensha.org/File-Formats for more information.

File descriptions:

Branch Averaged Files

These files contain branch-averaged fault system solutions, where rupture properties (magnitude, rake, rate of occurrence, etc) are averaged across all UCERF3 logic tree branches, according to each branch's weighting in the final model. This is the simplest version of the model, and can be used as a quick approximation to mean hazard. One file exists for each fault model, and these files are compatible with the time-dependent version of UCERF3.

• branch_averaged_ucerf3_sol_FM3_1.zip - fault model 3.1 branch averaged fault system solution
• branch_averaged_ucerf3_sol_FM3_2.zip - fault model 3.2 branch averaged fault system solution

Full Model (Compound Solutions)

These files contain the full UCERF3 logic tree, and can be used to extract data for individual logic tree branches (e.g., for use in hazard calculations that consider all epistemic uncertainties).

• full_ucerf3_compound_sol.zip - full compound solution file with information on all 1,440 time-independent logic tree branches
• full_ucerf3_compound_sol_with_individual_runs.zip - same as above, but also containing rates for each of 10 simulated annealing inversion runs for each logic tree branch (total of 14,400 inversions)

True Mean Solutions

A different type of branch averaged solution, the “true mean” solution, is also available. They are similar to the branch averaged fault system solution described above, but instead use duplicate versions of each rupture whenever a key property (rake, magnitude, area) changes. This retains all variability allowing for quick reproduction of mean UCERF3 results with a minimum set of ruptures. The MeanUCERF3 ERF implemented in OpenSHA uses these files and also allows the user to apply various approximations to further reduce the rupture count.

Note: These solutions are not compatible with time dependent UCERF3 calculations as multiple instances of each subsection may exist, resulting in rate partitioning between instances and incorrect recurrence intervals for renewal model calculations.

• true_mean_ucerf3_sol.zip - true mean fault system solution, across both fault models
• true_mean_ucerf3_sol_FM3_1.zip - true mean fault system solution, only for fault model 3.1
• true_mean_ucerf3_sol_FM3_2.zip - true mean fault system solution, only for fault model 3.2

Metadata

A copy of the original file format description is included in file_format.md, and is also available online here. A CSV file that includes information on each gridded seismicity location is also included (relm_gridded_region.csv).