Scenarios of T-wave Excitation by Teleseismic Earthquakes in the Western Pacific

• Main Authors: Wen-Hong Wei, 魏文宏
• Other Authors: Po-Fei Chen
• Format: Others
• Language: zh-TW
• Published: 2010
• Online Access: http://ndltd.ncl.edu.tw/handle/98089094048471489665

碩士 === 國立中央大學 === 地球物理研究所 === 98 === We used seismic station array on the margin of the Western Pacific to examine the controlling factors of earthquakes in the Izu-Bonin-Mariana subduction zone to excite T waves. The observed excited T waves in turn were used to investigate the decisive parameters for receiver-side acoustic-to-elastic conversion, in a quantitative fashion by the Gamma calculation. Having examined earthquakes in 2005, 17 out of 48 are T-excited events. We have discovered a preferential source-receiver pair for observations of T waves, namely, earthquakes in the southern Mariana Arc as recorded by stations in East Taiwan coastline. Additionally, the T-excited events correlate strongly with normal faulting type of earthquakes. While the strong curvature of the mid-SOFAR isobaths in the South Mariana Arc and the nearly perpendicular incidence to the receiver shoreline of earthquakes herein are conceptually attributed the preferential pair, the correlation with normal-faulting earthquakes needs to be cautiously examined by further studies. On the receiver side, the steeply dipping slopes of the East Taiwan coasts act as efficient interfaces for acoustic-to-elastic conversion. The converted T-waves can be recorded by stations even 50 km inland. The angles between incidence and receiving shoreline also determine the efficiency of receiver-side conversion.