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Seismic anisotropy of the upper mantle beneath Thailand:Tectonic setting constrained by shear-wave splitting analysis |
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| รหัสดีโอไอ | |
| Creator | 1. Wisawet Wongwai 2. Passakorn Pananont 3. Eric Sandvol 4. Kevin Furlong |
| Title | Seismic anisotropy of the upper mantle beneath Thailand:Tectonic setting constrained by shear-wave splitting analysis |
| Publisher | Research and Development Office, Prince of Songkla University |
| Publication Year | 2563 |
| Journal Title | Songklanakarin Journal of Science and Technology |
| Journal Vol. | 42 |
| Journal No. | 5 |
| Page no. | 1098-1105 |
| Keyword | Thailand, tectonic setting, shear-wave splitting |
| URL Website | https://rdo.psu.ac.th/sjstweb/index.php |
| ISSN | 0125-3395 |
| Abstract | The tectonic setting of the lithosphere and upper mantle underneath Thailand varies and changes substantially overshort distances. We have mapped these variations using shear wave splitting (SWS) analysis. We have determined the shear wavesplitting fast polarization azimuth (?) and delay time (?t) using the grid search method with the assumption of a flat, single-layerupper-mantle anisotropy. The data set was constructed using 117 teleseismic earthquakes with magnitudes greater than 5.8, andepicentral distances between 80 and 180 degrees that occurred between 2009 and 2013, using earthquake information fromUSGS Comprehensive Earthquake Catalog. This resulted in 425 observations with clear P-wave arrivals, SKS, and SKKSphases. Our results show that 70% of the stations (15 of 22 stations) on the Shan-Thai terrane have N-S fast orientations and anaverage delay time of 0.7?0.2 seconds. 100% of the stations (14 stations) located on the Indochina terrane have dominantly E-Wfast orientations and an average delay time of 0.8?0.2 seconds. This point supports the interpretation that on a lithospheric scale,Thailand consists of two major terranes. |
