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.
|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|
|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) .|
|Department of Geology|
|University of Maryland, College Park, Maryland|
|Berkeley Seismological Laboratory|
|University of California, Berkeley|
|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)|
|SEMUM original files and scripts: https://seismo.berkeley.edu/~barbara/SEMum_dist.tar.gz|
SEMUM model expressed as velocity perturbation relative to the reference model:
SEMUM_percent.nc (see metadata ), is the netCDF file for the model
|SEMUM model expressed in km/s:
SEMUM_kmps.nc (see metadata ), is the netCDF file for the model
|Depth Coverage||Whole Mantle (80 to 2850 km)|
|Area||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).|
To cite the original work behind this Earth model:
- 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. https://doi.org/10.1111/j.1365-246X.2011.04969.x.
To cite IRIS DMC Data Products effort:
- 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 Applications, Seismological Research Letters, 83(5), 846–854, https://doi.org/10.1785/0220120032.
DOI for this EMC webpage:
- 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.
Model provided by Ved Lekic