When an earthquake strikes, the release of energy creates seismic waves that often wreak havoc for life at the surface. Working with OLCF staff, the team continues to push the limits of computational seismology to deeper depths. After trying out its method on smaller machines, Tromp's team gained access to Titan in 2013 through the Innovative and Novel Computational Impact on Theory and Experiment, or INCITE, program. In 2012, just such a machine arrived in the form of the Titan supercomputer, a 27-petaflop Cray XK7 managed by the US Department of Energy's (DOE's) Oak Ridge Leadership Computing Facility (OLCF), a DOE Office of Science User Facility located at DOE's Oak Ridge National Laboratory. The problem with testing this theory? 'You need really big computers to do this,' Bozdag said, 'because both forward and adjoint wave simulations are performed in 3-D numerically.'

This technique leverages more information than competing methods, using forward waves that travel from the quake's origin to the seismic receiver and adjoint waves, which are mathematically derived waves that travel from the receiver to the quake. To fill in gaps within seismic data maps, the theory posited a method called adjoint tomography, an iterative full-waveform inversion technique. The project's genesis can be traced to a seismic imaging theory first proposed in the 1980s. For the first time, we showed people the value and feasibility of running these kinds of tools for global seismic imaging.' 'That's a milestone for the seismology community. 'This is the first global seismic model where no approximations - other than the chosen numerical method - were used to simulate how seismic waves travel through Earth and how they sense heterogeneities,' said Ebru Bozdag, a coprincipal investigator of the project and an assistant professor of geophysics at the University of Nice Sophia Antipolis. Created using data from 253 earthquakes captured by seismograms scattered around the world, the team's model is notable for its global scope and high scalability. In 2016, the team released its first-generation global model. These high-fidelity simulations add context to ongoing debates related to Earth's geologic history and dynamics, bringing prominent features like tectonic plates, magma plumes, and hotspots into view. Currently, the team is focused on imaging the entire globe from the surface to the core-mantle boundary, a depth of 1,800 miles. Using advanced modeling and simulation, seismic data generated by earthquakes, and one of the world's fastest supercomputers, a team led by Jeroen Tromp of Princeton University is creating a detailed 3-D picture of Earth's interior.

Clever imaging techniques devised by computational scientists, however, offer the promise of illuminating Earth's subterranean secrets. But unlike an onion, peeling back Earth's layers to better explore planetary dynamics isn't an option, forcing scientists to make educated guesses about our planet's inner life based on surface-level observations.

Google earth 3d earthquake map