[S-IT14] 地球深部科学

[SIT14-P12] Preliminary measurements of the splitted shear wave beneath Thailand by Thai Seismic Array (TSAR)

*Tarudee Autaijaratrasmee^1,2、Satoru Tanaka²、Kenji Kawai¹、Sutthipong Noisagool³ (1.University of Tokyo、2.Japan Agency for Marine-Earth Science and Technology、3.Mahidol University)

キーワード：Shear wave splitting, Transverse energy minimization method, Fast polarization direction, Delay time of the split shear wave

We measured polarization and delay-time of shear wave splitting of SKS observed at 35 broadband stations of the Thai seismic array (TSAR; Tanaka et al., 2019) from 8 deep Fiji earthquakes in 2017 using the minimization energy method (Silver and Chan, 1991). To date, we have obtained 116 measurements for splitted data and no-splitted, which consist of the fast polarization direction (phi) and delay time of the split shear wave (delta t). Preliminary results for splitted data show the fast directions roughly aligned in the west to east (W-E) direction with the absolute average value of 73.15 degrees (from 0 to 180 degrees) and the observed delay times ranging from 0.50 to 2.00 s with an average of 1.26 s. In the presentation, we will discuss the uncertainties of the orientation of the horizontal components of seismometers for phi and delta t and mantle flow in the upper mantle beneath Thailand.