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Viscoelastic (Maxwell) relaxation of stresses from a single, finite, dip-slip earthquake in 3D without body forces. The analytical solution for the elastic displacement (available at geoweb.mit.edu/fe) is applied at the boundaries and held fixed through time.

*Benchmark #5a*: For at least 1 run, evaluate the model behavior on a specified mesh (available at geoweb.mit.edu/fe). Also investigate other meshes (grid spacing, element types, etc.) as allowed by the code.

*Benchmark #5b*: Using a mesh of your choice, investigate accuracy as a function of the number of nodes near the fault tip. Also consider variations in how the discrete fault tip is buried within the viscoelastic medium (i.e., # of nodes in transition, transition distance, etc.).

*Benchmark #5c*: Approximate pinned boundaries at infinite distances from the fault (either using infinite elements or extending the boundaries a far distance from the fault, using mesh grading).

- Benchmark #5a: Evaluate accuracy efficiency of codes as a function of meshing technique and element type.
- Benchmark #5a: Code comparison.
- #5b: Test accuracy of code near fault tip.
- Benchmark #5b: Investigate 'best' methods for 1) discretizing the mesh near the fault tip and 2) approximating the brittle-ductile transition.
- Benchmark #5c: Comparison to semi-analytical solutions (e.g. VISCO1D).

- Model size: 24 km by 24 km by 24 km (0 km ≤ x; y ≤ 24 km; -24 km ≤ z ≤ 0 km)

Top layer: -12 km ≤ z ≤ 0 km; Bottom layer: -24 km ≤ z ≤ -12 km - Elastic material properties: Poisson solid, G = 30 GPa
- Maxwell viscoelastic material properties:

Top layer: η = 10^{25 }Pa-s (essentially elastic)

Bottom layer: η = 10^{18 }Pa-s - Density and Gravity: None
- Boundary conditions:

Bottom and all sides except the symmetry plane (y = 0 km) have analytical solution imposed (available atgeoweb.mit.edu/fe)

Side at y = 0 km has 0 y-displacement (i.e., symmetry condition applied)

Top free - Coarse mesh node spacing: dx = dy = dz = 2 km
- Fault specifications:

Type: 45° dipping fault

Location: Top edge at x = 4 km; Bottom edge at x = 20 km

0 km ≤ y ≤ 16 km; -16 km ≤ z ≤ 0 km - Slip distribution: 1 m of uniform thrust slip (0.707 m in the z-direction and -0.707 m in the x-direction) for 0 km ≤ y ≤ 12 km and -12 km ≤ z ≤ 0 km with a linear taper to 0 slip at y = 16 km and z = -16 km.

Mesh Variations: As memory, time, and patience allow, run models at 1/2, 1/4, and ^{1}/_{8}, etc. the original coarse mesh spacing, investigate variable mesh spacing, and/or employ a variety of element types.

For All Benchmark Variations:

- Stresses and displacements along three lines parallel to the y-axis at 0, 1, and 5 km from the fault plane at the depths of 0, 12, 16, 17, and 21 km (e.g. at the surface x=4, 5, and 9 km, at z = -12, x=16, 17, and 20 km); and three lines parallel to the x-axis at y = 12, 17, and 21, at depths of 0, 12, 16, 17 and 21 below the surface, all results at times of 0, 1, 5 and 10 years.
- CPU time, wallclock time, memory usage info, compiler info, and platform info