SKS/SKKS Splitting Parameters beneath GSN Stations: A Web-Based Database


Shear wave splitting is the most unambiguous manifestation of anisotropy available to seismologists. The two splitting parameters determined using SKS/SKKS phases, the fast polarization direction and the splitting delay time, are important constraints on the orientation and magnitude of mantle deformation, respectively. During the past decade, significant improvement has been made in the techniques for the determination of shear wave splitting parameters, in the operation of seismic networks, and in the speed of computers and the Internet. These advances make the rapid and routine determination of shear wave splitting parameters a feasible and worthwhile goal. We have developed a near-automatic procedure for such a purpose. Extensive testing using all the broadband data from magnitude $\geq$5.8 earthquakes recorded by about 100 GSN stations suggests that the procedure is fast, stable, and reliable, and only requires minimal quality control from experienced seismologists. The mean number of events per station is about 30. For a given station, we plan to produce at least the following products and post them on the worldwide web (see address below): (1). splitting parameters made using single event-station pairs; (2). splitting parameters made by stacking events from fixed back azimuths; (3). splitting parameters made by stacking events occurred within a certain time period; and 4). azimuthal variation of splitting parameters. Those products can be used for many purposes. For instance, in addition to the traditional ones such as detecting asthenospheric flow and exploring effects of ancient tectonic events, possible temporal variations of splitting parameters might be used to study tectonic transients.

Meeting Name

AGU Fall Meeting (2001: Dec. 10-14, San Francisco, CA)


Geosciences and Geological and Petroleum Engineering

Keywords and Phrases

SEISMOLOGY; Body waves; Lithosphere; Seismic instruments and networks

Document Type

Article - Conference proceedings

Document Version


File Type





© 2001 American Geophysical Union (AGU), All rights reserved.

Publication Date

01 Dec 2001

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