The future Community-Driven SCEC SEAS Code Comparisons for [1] Three-Dimensional fluid injection and [2] a Two-Dimensional dipping fault with variable normal traction.

The Statewide California Earthquake Center (SCEC) sequence of earthquake and aseismic slip (SEAS) group has regularly developed and published benchmarks along the years to follow recent development in the modeling of sequences of aseismic slip and earthquakes, as well as progress in numerical methods. These benchmarks, as well as the results from the different groups are publicly available at: https://strike.scec.org/cvws/seas/. It provides both reference solutions for code verification and a framework for systematic comparison of different modeling approaches. Every group is welcomed to join this Community driven comparison.

Recent efforts have focused on adding physics to better reproduce earthquake cycle by considering 2-dimensional fault (Jiang et al., 2022), improve our understanding of fluid injection processes (Lambert et al., 2025), and the effect of free surface and dipping fault (Erickson et al., 2023).

To follow up these developments, the SCEC SEAS group is designing two new benchmarks, that will be released to the community soon:

[1] A generalization of our benchmark about fluid injection (BP6) from a 2-dimensional domain to 3-dimensional domain. In this benchmark pore fluid diffuses along a 2-dimensional fault, modifying the effective normal traction  through one-way hydromechanical coupling. The fluid is injected for 10 hours on a rate strengthening faut and then shut off. The benchmark is designed to admit an analytical formulation for pore fluid diffusion while avoiding numerical singularities that may occurred with point source injection. For this reason, fluid is injected along a Gaussian profile.

[2] An updated version of our previous dipping fault benchmark (BP3), in a two-dimensional medium with a free surface. Previous version assumed that the normal traction along the fault was constant.  This is obviously a strong assumption, because the normal traction should increase with depth. However, this has proven to be difficult to simulate numerically as the system is going stiffer with lower normal traction. This benchmark therefore aims at providing a more realistic simulation of a dipping fault with a free surface by introducing depth dependent normal traction while also testing the ability of different numerical code to circumvent the problem of stiffness. This benchmark will be a joint benchmark with CRESCENT (Cascadia Region Earthquake Science Center).

This contribution will present the design of these forthcoming benchmarks and will provide an opportunity for the community to discuss about future benchmarks and directions for SEAS code comparison efforts.