all SSK database entries, station averaged
all SKS database entries, 2 by 2 degree averaged
Here, we provide an update of the SKS splitting databased of
et al., 2012, new version as of December 06, 2020.
This work was made possible by the willingness of seismologists to
share their results, and our database is largely based on, and
reusing, the compilation efforts of G. Barruol, A. Wüstefeld, M.
Fouch, D. Schutt, and P. Silver. In particular, our database is not
meant to reproduce the ongoing efforts by G. Barruol to keep
et al.'s (2009) SKS database updated.
However, our compilation does hold back-azimuth and event data for
some of the studies, information not available for some of the other
compilations. References for the source data bases we use include:
We continue to update our SKS splitting database. The newest
version (as of December 06, 2020) can be found below, the format is
described in the README for the old version of the database above:
We also have generalized spherical harmonics expansions of those data,
please contact me if interested.
In addition to merging existing compilations and adding back-azimuth
information to many of the studies, we are adding a small number of
individual studies not found (fully, at the time of merging) in the
other compilations, some of which are listed below.
- Wüstefeld, A. and Bokelmann, G. H. R. and Barruol, G. and
Montagner, J. P.: Identifying global seismic anisotropy patterns by
correlating shear-wave splitting and surface-wave
data, Phys. Earth Planet. Int., 176, 198-212, 2009.
Database available online at
(Version as of 05/2011 was used for
Becker et al., 2012; for the current
version, see below).
- Fouch, M.: Upper Mantle Anisotropy Database, was at
http://geophysics.asu.edu/anisotropy/upper/, accessed 06/2006, 2006.
- Silver, P. G.: Seismic anisotropy beneath the continents: probing
the depths of geology, Ann. Rev. Earth Planet. Sci., 24,
Besides the studies used for
Becker et al. (2012), we currently include additional work by several
additional studies including those listed below:
For reproducibility, we here provide the SKS splitting
database that was used for our study on global mantle azimuthal
You might want to use
Wüstefeld's SKS database instead
(or the IRIS mirror), which have more
complete references to original studies, and a very nice map and
search interface. However, our SKS database tries to maintain
- An updated
(01/10/2021) version of Barruol and Wuestefeld et al.'s (2009)
splitting database (IRIS copy).
- Anderson, M. L., G. Zandt, E. Triep, M. Fouch, and S. Beck (2004):
Anisotropy and mantle flow in the Chile-Argentina subduction zone
from shear wave splitting analysis, Geophys. Res. Lett.,
31, L23608, doi:10.1029/2004GL020906.
- Di Leo, J. F., J. Wookey, J. O. S. Hammond, J.-M. Kendall,
S. Kaneshima, H. Inoue, T. Yamashina, and P. Harjadi (2012), Mantle
flow in regions of complex tectonics: Insights from Indonesia,
Geochem. Geophys. Geosyst., 13, Q12008,
- MacDougall, J. G., K. M. Fischer, and M. L. Anderson (2012),
Seismic anisotropy above and below the subducting Nazca lithosphere in
southern South America, J. Geophys. Res., 117, B12306,
- Leon Soto, G., E. Sandvol, J. F. Ni, L. M. Flesch, T. M. Hearn,
F. Tilmann, Y. J. Chen, and L. Brown (2012): Significant and
vertically coherent seismic anisotropy beneath Eastern
Tibet. J. Geophys. Res., doi:10.1029/2011JB008919.
- Hicks, S. P., Nippress, S. E. J., Rietbrock, A. (2012), Sub-slab
mantle anisotropy beneath south-central Chile, Earth
Planet. Sci. Lett., 357, 203-213.
- Miller, M. S., Allam, A. A., Becker, T. W. and Di Leo, J., and
Wookey, J. (2013): Constraints on the geodynamic evolution of the
westernmost Mediterranean and northwest Africa from shear wave
splitting analysis. Earth Planet. Sci. Lett., 375,
- Refayee, H. A., B. B. Yang, K. H. Liu, and S. S. Gao (2013):
Mantle flow and lithosphere-asthenosphere coupling beneath the
southwestern edge of the North American Craton: Constraints from
shear-wave splitting measurements, Earth Planet. Sci. Lett.,
- Calixto, F. J., D. Robinson, E. Sandvol, S. Kay, D. Abt,
K. Fischer, B. Heit, X. Yuan, D. Comte, and P. Alvarado (2014):
Shear wave splitting and shear wave splitting tomography of the
southern Puna plateau, Geophys. J. Int., 199, 688-699.
- Porritt, R. W., Becker, T. W., and Monsalve, G. (2014): Seismic
anisotropy and slab dynamics from SKS splitting recorded in
Colombia. Geophys. Res. Lett., 41,
- Diaz, J. and J. Gallart (2014): Seismic anisotropy from the
Variscan core of Iberia to the Western African Craton: New constrains
on upper mantle flow at regional scales, Earth
Planet. Sci. Lett., 394, 48-57.
- Bastow I. D, Julia J., do Nascimento A. F., Fuck R.A., Buckthorp,
T.L., McClellan, J., J. et al. (2015): Upper mantle anisotropy of
the Borborema Province, NE Brazil: Implications for intra-plate
deformation and sub-cratonic asthenospheric flow, Tectonophys.,
- Bodmer, M., Toomey, D. R., Hooft, E. E., and Braunmiller, J. (2015)
Seismic anisotropy beneath the Juan de Fuca plate system: Evidence
for heterogeneous mantle flow, Geology, 43, doi:G37181.1.
- Hodges, Michael, and Meghan S. Miller. Mantle flow at the
highly arcuate northeast corner of the Lesser Antilles
subduction zone: Constraints from shear-wave splitting
analyses. Lithospher, 7, 579-587, 2015.
- Idarraga-García, J., Kendall, J. .-M. and Vargas, C. A. (2016),
Shear wave anisotropy in northwestern South America and its link to
the Caribbean and Nazca subduction
geodynamics. Geochem. Geophys. Geosyst.,
- S. Subašić, S. Prevolnik, D. Herak, and M.
Herak. Observations of SKS splitting beneath the Central and
Southern External Dinarides in the Adria-Eurasia convergence
- McPherson, A. M., Christensen, D. H., Abers, G. A., and Tape,
C. (2020). Shear wave splitting and mantle flow beneath
Alaska. J. Geophy. Res., 125,
- Estève, C. and P. Audet, A. J. Schaeffer, D. L. Schutt,
R. C. Aster, and Joel F. Cubley (2020). Seismic evidence for craton
chiseling and displacement of
lithospheric mantle by the Tintina fault in the northern Canadian
Cordillera. Geology, doi:10.1130/G47688.1.
Our study included Wuestefeld et al.'s (2009) database in the 05/2011
version, with partially augmented information such as back-azimuths,
along with several additional studies, including:
- Becker, T. W., Lebedev, S., and Long, M. D.: On the relationship
between azimuthal anisotropy from shear wave splitting and
tomographic models. J. Geophys. Res., 117, B01306,
After removal of textual exact duplicates, the individual split
compilation as of
et al. (2012) contained 14,326 entries including nulls. This
compilation does hold, however, actual duplicate data entries with
different notation (e.g. slight differences in station location
accuracy) which are removed in a next step. Moreover, not all
original papers provided event information (needed for
back-azimuthally-dependent averaging) and only some of the entries in
the databases distinguished between individual splits and
station-averages. We therefore proceeded to process the
original SKS splits by performing a simple, arithmetic
average for all (approximately) co-located entries. This yielded 5,159
averaged entries; both data bases are provided for download below:
- Fouch, M.J., and J.D. West (2011): The mantle flow field beneath
the western United States, in prep.
- Civello S., Margheriti L. (2004): Toroidal mantle flow around the
Calabrian slab (Italy) from SKS splitting, Geophys. Res. Lett.,
Updated: June 14, 2021.
(c) Thorsten W. Becker, 1997-2021.