Researchers at the Japan Agency for Marine-Earth Science and Technology (JAMSTEC) reported simulating global seismic wave propagation with a best-ever accuracy of 1.2 sec seismic period for a three-dimensional Earth model on Japan’s K supercomputer. Optimizing the code allowed them achieve sustained performance of 1.24 petaflops on the K computer, which is 11.84% of its peak performance.
Their work is reported in the International Journal of High Performance Computing Applications (A 1.8 trillion degrees-of-freedom, 1.24 petaflops global seismic wave simulation on the K computer, Feb. 28). The study will help understand earthquake occurrence mechanisms and the Earth’s internal structures more precisely and is expected to make significant contributions to disaster prevention and mitigation.
As noted in the abstract from their paper, the work was computationally challenging:
“…Our seismic simulations use a total of 665.2 billion grid points and resolve 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, that is, parallel efficiency on 82,134 nodes relative to 36,504 nodes is 99.54%…”
The research group was led by Dr. Seiji Tsuboi at Center for Earth Information Science and Technology (CEIST). In 2003, a similar study group achieved the computed theoretical seismograms with what was then a record-breaking 5 second frequency for realistic three -dimensional Earth with the Earth Simulator.
Links to today’s press release and the paper are below:
Press Release: http://www.jamstec.go.jp/e/about/press_release/20160317/
Paper: http://komatitsch.free.fr/preprints/Tsuboi_IJHPC_2016.pdf