Welcome to the online home of the SEMum2 model, a global radially anisotropic shear-velocity model of the earth's upper mantle and transition zone.
This is the companion website to the SEMum2 model, presented in our recently published paper:
French, S.W., V. Lekic, and B. Romanowicz (2013), Waveform Tomography Reveals Channeled Flow at the Base of the Oceanic Asthenosphere, Science, accepted (Science Express).
The SEMum2 model represents an update to the model SEMum , incorporating an improved treatment of Earth's crust and inversion for shorter-wavelength mantle structure. Both models employ a "hybrid" full-waveform inversion methodology, combining accurate forward modeling of the seismic wavefield using the spectral element method (SEM)  with finite-frequency sensitivity kernels from non-linear asymptotic coupling theory (NACT) . Together with the use of a smooth crustal model that mimics the seismic response of Earth's crust, this approach leads to considerable savings in computational cost.
Download the model distribution and evaluation tool (2.8M) here (
This gzipped tar file (expand:
tar xzf SEMum2_dist-v0.1.tar.gz)
contains the raw spline-basis coefficients for the model, as well
as a tool for evaluation at arbitrary (lon,lat) points and on regular
grids at a specified radius. The latter is written in C and should
compile without issue using, for example, the GNU C compiler.
More functionality for model evaluation will be added, so do check back for updated versions of this package.
Please report any bugs to Scott French (contact).
The SEMum2 model was developed at the Berkeley Seismological Laboratory. Contact the authors:
|Scott French||sfrench at seismo dot berkeley dot edu||Berkeley Seismological Laboratory, U.C. Berkeley|
|Vedran Lekic||ved at umd dot edu||University of Maryland|
|Barbara Romanowicz||barbara at seismo dot berkeley dot edu||Berkeley Seismological Laboratory, U.C. Berkeley; Institut de Physique du Globe de Paris, Paris, France|