11:15 AM - 11:30 AM
[STT61-03] Global seismic wave computation on the K computer
Keywords:seismic wave ppropagation, spectral element method, K computer
1.8 trillion degrees of freedom. To realize these large-scale computations, we optimize a widely used community software code to efficiently address all hardware parallelization, especially thread-level parallelization to solve the bottleneck of memory usage for coarse-grained parallelization. The new code exhibits excellent strong scaling for the time stepping loop, i.e. parallel efficiency on 82,134 nodes relative to 36,504 nodes is 99.54%. Sustained performance of these computations on the K computer is 1.24 petaflops, which is 11.84% of its peak performance. The obtained seismograms with an accuracy of 1.2 seconds for the entire globe should help us to better understand rupture mechanisms of devastating earthquakes.
This work used computational resources of the K computer provided by the RIKEN Advanced Institute for Computational Science through the HPCI System Research project (Project ID:hp130013). We used the open-source SPECFEM3D GLOBE version 5 software package freely available through the Computational Infrastructure for Geodynamics (CIG). Broadband seismograms were recorded by the Global Seismic Network and distributed by the IRIS Data Management Center.