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)|
|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.|
|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).|
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, http://doi:10.1785/0220120032.
To cite the source of 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
To reference the use of this Earth model hosted by EMC:
- IRIS DMC (2013), Data Services Products: SEMum, a high-resolution global model of upper mantle structure, http://doi:10.17611/DP/9991866.
To cite IRIS Earth Model Collaboration (EMC) data product or reference use of its repository:
- IRIS DMC (2011), Data Services Products: EMC, A repository of Earth models, http://doi:10.17611/DP/EMC.1.
- 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.
V. Lekic and B. Romanowicz