UCERF3 ERFs Available in OpenSHA

UCERF3 is a complex model comprised of many logic tree branches. Multiple ERFs are implemented in OpenSHA allowing users to access either a single logic tree branch or a mean model. This page describes the different ERFs available and their uses/caveats.

Fault System Solution ERF

Class name: scratch.UCERF3.erf.FaultSystemSolutionERF

This is the base class of all UCERF3 related ERFs, although it is also applicable to any FaultSystemSolution. It allows you to browse for a solution zip file, such as the branch averaged fault system solutions explained below

Branch Averaged Fault System Solutions

These solutions are an approximate mean model for a single Fault Model. Each rupture rate, magnitude, and rate is the weighted mean of all 720 time independent logic tree branches for that Fault Model. This means that magnitude and rake variability is discarded for a single mean value. Additionally, fault geometries can vary between logic tree branches due to aseismicity factors - this solution uses aseismicity factors derived from branch averaged slip rates. They are useful for quick calculations, but can vary substantially from the true model especially near dipping faults with variable aseismicity among logic tree branches.

Time independent hazard curves calculated with these solutions will differ from true mean (curves that were calculated for each logic tree branch independently then averaged) by 0-7%. They can be downloaded here:

Fault Model 3.1: ​http://opensha.usc.edu/ftp/kmilner/ucerf3/2013_05_10-ucerf3p3-production-10runs/2013_05_10-ucerf3p3-production-10runs_COMPOUND_SOL_FM3_1_MEAN_BRANCH_AVG_SOL.zip Fault Model 3.2: ​http://opensha.usc.edu/ftp/kmilner/ucerf3/2013_05_10-ucerf3p3-production-10runs/2013_05_10-ucerf3p3-production-10runs_COMPOUND_SOL_FM3_2_MEAN_BRANCH_AVG_SOL.zip