The shear-wave splitting measurements for western and central United States is a teleseismic shear-wave splitting (SWS) database based on all the data from all the broadband seismic stations in North America that contains over 16,000 pairs of well-defined (and manually checked) SWS measurements for the western and central United States (west of 90°W).
Measurements of the strength and direction of seismic anisotropy from splitting of teleseismic P-to-S converted phases at the core-mantle boundary on the receiver side, such as SKS, SKKS, and PKS (collectively called XKS, figure to the right) provide important information on the mechanical anisotropy of the earth’s crust and upper mantle in the form of SWS parameters:
- fast polarization direction (φ)
- splitting time between the fast and slow split shear-waves (δt)
These parameters are measures of the orientation and strength of the anisotropy.
The Missouri S&T western and central United States shear-wave splitting database uses all the available broadband seismic data archived at the IRIS DMC in the western and central United States (west of 90°W), from teleseismic events occurred between 1980-01-01 and early 2013. Seismic waveforms from events with magnitude ≥ 5.6, which is reduced to 5.5 if the focal depth is greater than 100 km to take the advantage of sharper waveforms from deeper earthquakes, and in the epicentral distance range of 84°-180° are requested from the DMC. The data are band-pass filtered in the frequency band of 0.04-0.5 Hz which includes the main XKS energy.
Database Download (version 1308)
- Go to the Missouri S&T shear-wave splitting database repository
- Download the related computer codes (coming soon)
- View the Missouri S&T shear-wave splitting database README
- View the Missouri S&T shear-wave splitting database content as text
- Download the Missouri S&T shear-wave splitting database
The database contains 16,105 pairs of shear-wave splitting parameters for western and central United States (go to the database repository). The entire database is available as a text file with 17 columns, as listed below.
The columns in the database:
- Station_network name
- Phase name
- Event name
- Station latitude
- Station longitude
- Fast polarization direction
- The standard deviation of the fast direction
- Splitting time
- The standard deviation of the splitting time
- Back azimuth, measured clockwise from the North
- Modulo-90 degree back-azimuth
- Event latitude
- Event longitude
- Event depth
- Measurement quality
- Longitude of XKS raypiercing point at 200 km depth
- Latitude of XKS raypiercing point at 200 km depth
To cite the IRIS DMC Data Products effort:
- Hutko, A. R., M. Bahavar, C. Trabant, R. T. Weekly, M. Van Fossen, T. Ahern (2017), Data Products at the IRIS‐DMC: Growth and Usage, Seismological Research Letters, 88, no. 3, https://doi.org/10.1785/0220160190.
To cite the IRIS DMC Shear-wave splitting databases or reference use of its repositories:
- IRIS DMC (2012), Data Services Products: SWS-DBs Shear-wave splitting databases, https://doi.org/10.17611/DP/SWS.1.
To cite the source or reference the use of Missouri S&T Shear-wave splitting database:
- Bin B. Yang, Kelly H. Liu, Haider H. Dahm, and Stephen S. Gao (2016), A Uniform Database of Teleseismic Shear‐Wave Splitting Measurements for the Western and Central United States: December 2014 Update, Seismological Research Letters, https://doi.org/10.1785/0220150213
- Liu, K.H., A. Elsheikh, A. Lemnifi, U. Purevsuren, M. Ray, H. Refayee, B. Yang, Y. Yu, and S.S. Gao (2014), A uniform database of teleseismic shear wave splitting measurements for the western and central United States, Geochemistry Geophysics Geosystems , https://doi.org/10.1002/2014GC005267
- Yang, B.B., S.S. Gao, K.H. Liu, A.A. Elsheikh, A.A. Lemnifi, H.A. Refayee, and Y. Yu (2014), Seismic anisotropy and mantle flow beneath the northern Great Plains of North America, Journal of Geophysical Research, , volume 119, https://doi.org/10.1002/2013JB010561
Most of the measurements below (version 1308) are described in the following publications:
- Liu, K.H., A. Elsheikh, A. Lemnifi, U. Purevsuren, M. Ray, H. Refayee, B. Yang, Y. Yu, and S.S. Gao (2014), A uniform database of teleseismic shear wave splitting measurements for the western and central United States, Geochemistry Geophysics Geosystems , doi: 10.1002/2014GC005267
- Liu, K.H. (2009), NA-SWS-1.1: A uniform database of teleseismic shear-wave splitting measurements for North America, Geochemistry, Geophysics, Geosystems, 10, Q05011, doi:10.1029/2009GC002440
- 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 and Planetary Science Letters , 10.1016/j.epsl.2013.01.031.
- Yang, B.B., S.S. Gao, K.H. Liu, A.A. Elsheikh, A.A. Lemnifi, H.A. Refayee, and Y. Yu (2014), Seismic anisotropy and mantle flow beneath the northern Great Plains of North America, Journal of Geophysical Research, , volume 119, doi: 10.1002/2013JB010561
In addition, the measurements were produced using the procedure described in the following paper:
- Liu, K.H, and S.S. Gao (2013), Making reliable shear-wave splitting measurements, Bulletin of the Seismological Society of America, Volume 103, No.5, 14 pages, doi: 10.1785/0120120355
- Liu, K. H., S. S. Gao, Y. Gao, and J. Wu (2008), Shear wave splitting and mantle flow associated with the deflected Pacific slab beneath northeast Asia, Journal of Geophysical Research, 113, B01305 (15 pages), doi:10.1029/2007JB005178
- Savage, M. K. (1999), Seismic anisotropy and mantle deformation: what we learned from shear-wave splitting?Rev. Geophys., 37, 65-106.
Geology & Geophysics Program
Missouri University of Science and Technology
Rolla, MO 65409, USA
The shear-wave splitting measurements for the western and central United States was provided under sub-award number 63-DMS, which was awarded under cooperative agreement No. EAR-0733069 issued by the NSF under CFDA No. 47.050.
Manochehr Bahavar, IRIS DMC
- Added Missouri S&T shear-wave splitting database