Issue No. 05 - September/October (2017 vol. 19)

ISSN: 1521-9615

pp: 27-37

Hans Johansen , Lawrence Berkeley National Laboratory

Arthur Rodgers , Lawrence Livermore National Laboratory

N. Anders Petersson , Lawrence Livermore National Laboratory

David McCallen , Lawrence Berkeley National Laboratory

Bjorn Sjogreen , Lawrence Livermore National Laboratory

Mamun Miah , Lawrence Berkeley National Laboratory

ABSTRACT

Modernizing SW4 for massively parallel time-domain simulations of earthquake ground motions in 3D earth models increases resolution and provides ground motion estimates for critical infrastructure risk evaluations. Simulations of ground motions from large (M ? 7.0) earthquakes require domains on the order of 100 to500 km and spatial granularity on the order of 1 to5 m resulting in hundreds of billions of grid points. Surface-focused structured mesh refinement (SMR) allows for more constant grid point per wavelength scaling in typical Earth models, where wavespeeds increase with depth. In fact, MR allows for simulations to double the frequency content relative to a fixed grid calculation on a given resource. The authors report improvements to the SW4 algorithm developed while porting the code to the Cori Phase 2 (Intel Xeon Phi) systems at the National Energy Research Scientific Computing Center (NERSC) at Lawrence Berkeley National Laboratory. Investigations of the performance of the innermost loop of the calculations found that reorganizing the order of operations can improve performance for massive problems.

INDEX TERMS

Earthquakes, Solid modeling, Computational modeling, Three-dimensional displays, Geology, Analytical models, Acceleration

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