HR: 1340h
AN: S43A-1067    [Abstracts]
TI: SORD: A New Rupture Dynamics Modeling Code
AU: * Ely, G
EM: gely@ucsd.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography University of California, San Diego 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AU: Minster, B
EM: jbminster@ucsd.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography University of California, San Diego 9500 Gilman Drive, La Jolla, CA 92093-0225 United States
AU: Day, S
EM: day@moho.sdsu.edu
AF: Deptartment of Geological Sciences, San Diego State University 5500 Campanile Drive, San Diego, CA 92182-1020 United States
AB: We report on our progress in validating our rupture dynamics modeling code, capable of dealing with nonplanar faults and surface topography. The method uses a "mimetic" approach to model spontaneous rupture on a fault within a 3D isotropic anelastic solid, wherein the equations of motion are approximated with a second order Support-Operator method on a logically rectangular mesh. Grid cells are not required to be parallelepipeds, however, so that non-rectangular meshes can be supported to model complex regions. However, for areas in the mesh which are in fact rectangular, the code uses a streamlined version of the algorithm that takes advantage of the simplifications of the operators in such areas. The fault itself is modeled using a double node technique, and the rheology on the fault surface is modeled through a slip-weakening, frictional, internal boundary condition. The Support Operator Rupture Dynamics (SORD) code, was prototyped in MATLAB, and all algorithms have been validated against known (including analytical solutions, eg Kostrov, 1964) solutions or previously validated solutions. This validation effort is conducted in the context of the SCEC Dynamic Rupture model validation effort led by R. Archuleta and R. Harris. Absorbing boundaries at the model edges are handled using the perfectly matched layers method (PML) (Olsen & Marcinkovich, 2003). PML is shown to work extremely well on rectangular meshes. We show that our implementation is also effective on non-rectangular meshes under the restriction that the boundary be planar. For validation of the model we use a variety of test cases using two types of meshes: a rectangular mesh and skewed mesh. The skewed mesh amplifies any biases caused by the Support-Operator method on non-rectangular elements. Wave propagation and absorbing boundaries are tested with a spherical wave source. Rupture dynamics on a planar fault are tested against (1) a Kostrov analytical solution, (2) data from foam rubber scale models, and (3) numerical results from other types rupture dynamics codes. We also test the case of a simple kinked fault that has a known analytical solution. SORD has now been ported to Fortran 95 for multi-processor execution, with parallelization implemented using MPI. This provides a modeling capability on large scale platforms such as the SDSC DataStar machine, the various Teragrid platforms, or the SCEC High-performance computing facility. We will report on progress in validating that version of the code.
DE: 7209 Earthquake dynamics (1242)
DE: 7290 Computational seismology
SC: Seismology [S]
MN: Fall Meeting 2005