Data Services Products: EMC-SEMum A high-resolution global model of upper mantle structure

Summary

SEMum is a radially anisotropic shear velocity model, parametrized in terms of isotropic S velocity (Voigt average) and the anisotropic parameter, xi (V sh 2 /V sv 2 ). The Vs (xi) model is parametrized in terms of 2562 (642) spherical splines laterally, and 16 irregularly spaced cubic b-splines radially.

Description

Name SEMum
Title A high-resolution global shear velocity model of upper mantle
Type 3-D full-waveform Earth Model
Sub Type A radially anisotropic shear velocity model
Year 2011
Short Description   SEMum is a radially anisotropic shear velocity model, parametrized in terms of isotropic S velocity (Voigt average) and the anisotropic parameter, xi (V sh 2 /V sv 2) based on a 1-D reference model (see Reference Model below) .
Authors:  
Ved Lekic
Department of Geology
University of Maryland, College Park, Maryland
Barbara Romanowicz
Berkeley Seismological Laboratory
University of California, Berkeley
Previous Model
Reference Model A smooth, modified version of PREM , with the Q structure of QL6 (Durek and Ekstrom, 1996) that fits normal mode frequencies (see Lekic & Romanowicz, 2011 for more information)
 
Model Download
gzip tarfile of original model files and scripts.
SEMUM_percent.nc (metadata ), is the netCDF binary for the above model expressed as velocity perturbation relative to the reference model (see Reference Model above).
SEMUM_kmps.nc (metadata ), is the netCDF binary for the above model expressed in km/s.
 
Model Homepage seismo.berkeley.edu/~lekic/SEMum.html
Depth Coverage Whole Mantle (80 to 2850 km)
Areal Coverage Global (-90°/90°, 0°/360°)
 
Data Set Description Dataset includes minor- and major-arc fundamental mode and overtone wavepackets from 200 earthquakes recorded at more than 100 broadband stations around the globe. In order to minimize the contamination from source complexity, all earthquakes have moment magnitude <7.0 (moment tensors and centroid locations are from the Harvard Centroid Moment Tensor Project).

SEMum horizontal slices

Figure, Lekic and Romanowicz (2011): maps of the Voigt average shear wave speed variations in Africa and surrounding oceans with respect to the average velocity at each depth. Note that the limits of colour scales change with depth and that the colours saturate in certain regions.

Citation

  • Lekic, V. and B. Romanowicz, 2011, Inferring upper-mantle structure by full waveform tomography with the spectral element method. Geophys. J. Int. 185(2), 799-831
  • Trabant, C., A. R. Hutko, M. Bahavar, R. Karstens, T. Ahern and R. Aster (2012), Data products at the IRIS DMC: stepping-stones for research and other application, Seismological Research Letters, 83(6), 846:854. doi: 10.1785/0220 120032

References

  • Durek, J.J. and Ekstrom, G. 1996. “A radial model of anelasticity consistent with long period surface wave attenuation.” Bull. Seism. Soc. Am. 86:144-158.

Credits

V. Lekic and B. Romanowicz

DOI

doi:10.1111/j.1365-246X.2011.04969.x

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