Short-Term Tectonics Priorities

Immediate, Urgent goals

• PyLith development (For more details see PyLith Development Plans)
  • Accelerate development via a postdoc
  • Nonlinear rheologies
  • Fault friction via cohesive cells
  • Large deformations
• Bring semi-analytic codes (layered elastic and viscoelastic, internal and surface loads) under version control. Add documentation as necessary and provide portability via a standard build procedure.
• Establish interaction with computational seismology group on meshing issues (e.g., keep up-to-date on the development of Geo-CUBIT).

Scientific Questions

• Observationally constrained and internally consistent physics for the entire seismic cycle

  Resolve the entire seismic cycle in simulations that capture interseismic deformation, rupture nucleation and propagation, and postseismic deformation with realistic Earth models (geometrical complexity, material heterogeneity, and inelastic rheologies). Simulations constrain the fault and bulk rheologies through extensive geodetic, seismic, and geologic observations. Constraints on fault and bulk rheologies are critical to understanding the behavior of fault systems and improving the accuracy and precision of earthquake hazard assessments.

• Observationally constrained and internally consistent physics for tectonics of magmatic systems, geothermal systems, and the cryosphere

  Integrate modeling tectonic processes with heat and fluid flow, thereby enabling complex rheologies with temperatue dependent parameters. Incorporating heat and fluid flow into tectonic modeling significantly expands the range of problems that can be solved and permits direct application of additional geophysical constraints. Viscoelastic, elastoplastic, and viscoplastic rheologies are important for bridging between seismic and tectonic time scales.

• Observationally constrained modeling of crustal deformation associated with surface loads

  Constrain the bulk rheologies of the crust using geodetic and geologic observations of deformation arising from glacial rebound, reservoir impounding, and other surface loads.

Potentially Relevant Computational Techniques

Need to assess the applicability and implications of using currently available and emerging computational techniques for earthquake modeling. Techniques may impose undesirable limitations on the geometry of the domain (e.g., topography) and faults or may introduce severe ill-conditioning of the system.

• Adaptive mesh refinement (e.g., deal.ii and p4est)

  Efficiently resolve evolving small length scale features through local refinement and coarsening of the mesh.

• Data assimilation and inversions

  Data assimilation aids in quantifying the uncertainty in parameters based on observations.

• Code generation (e.g., FEniCS)

  Generate optimized code for solution of specific problems using high-level tools

• Finite-element dicretization (e.g., X-FEM)

  Finite-element discretization techniques that permit resolution of dislocations and material boundaries within a structured grid. This would permit a structured mesh in problems with complex, nonplanar geometry.

• Multi-scale techniques

  Introduction of multiple spatial and temporal scales through homogenization. Resolution of multiple time scales through slow/fast timescale coupling.

Other tools

• Workflow management

  Streamline problem workflow using tools to manage inputs and outputs of the various stages of modeling (creating the geologic model, meshing the domain, simulating the physics, and post-processing the results).

• Establish community benchmarks for problems that cannot be solved by current software.

CIG Organizational Structure

• Software development
  • Must find the proper balance between providing software that is accessible to new users but also provides the flexibility and extensibility required by expert users.
  • Subcontracts for scientific driven cutting-edge development of community codes

    Provide funding for expert users to work with code developers to add new features to community codes in order to solve specific research problems.

• Training
  • Regular, multi-day workshops are essential for training the community in the use of state-of-the-art modeling codes and tools.
  • Additional complementary training is needed to provide different levels of training.
    • Short workshops at larger scientific meetings to expand the user base
    • Extended visits by computational scientists and software engineers to expert users and earth science developers and vice versa. This could be implemented via some form of travel grants for in-depth training.
    • Focused online training for new releases, common problems, and introduction to advanced features