LLNL-G3D-JPS: Global-scale Joint Tomography of P and S Wave Speeds in the Crust and Mantle

Wednesday, 17 December 2014
Nathan A Simmons1, Steve Myers1, Gardar Johannesson2, Eric Matzel2 and Steve Grand3, (1)Lawrence Livermore Nat'l Lab, Livermore, CA, United States, (2)Lawrence Livermore National Laboratory, Livermore, CA, United States, (3)University of Texas at Austin, Austin, TX, United States
We have combined a number of advanced techniques to construct a new global seismic tomography image of the Earth’s crust and mantle (LLNL-G3D-JPS). The image is produced via joint inversion of ~3 million high-quality arrival times for regional and teleseismic P and S waves including P, pP, pwP, Pn, Pg, Pb, PcP, S, sS, Sn, SS, ScS, SKS, and SKKS. The advanced techniques employed include a Bayesian global multiple-event relocation process (Bayesloc), 3-D ray tracing with multipath and mini-max phase considerations, and a multi-resolution inversion technique that exploits spherical tessellation hierarchies (called PMTI). The model consists of ~1.7 million model nodes and undulating structures are explicitly represented including 7 crustal units, the Moho, and the upper mantle phase transition boundaries. Although the image was produced primarily for accurate prediction of travel times for seismic event location applications, it also provides a valuable new image with key features important for understanding mantle evolution. This work performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-658071