An automatically updated S-wavemodel of the upper mantle and the depth extent of azimuthal anisotropy
An automatically updated S-wavemodel of the upper mantle and the depth extent of azimuthal anisotropy
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DOI：
10.1002/2015gl067329
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发表时间：
2016-01-28
影响因子：
5.2
通讯作者：
Durand, Stephanie
中科院分区：
文献类型：
--
作者：
Debayle, Eric;Dubuffet, Fabien;Durand, Stephanie
基于1976年以来记录的1,359,470次瑞利波波形建模，提出了上地幔S波模型3D2015_07Sv。近似正演理论和建模的使用允许用新数据定期更新模型。3D2015_07Sv包含方位角各向异性，横向分辨率接近600 km，与其他近期模型一致，最上层200 km为60度，过渡带为15度。尽管在大陆之下，径向各向异性比在海洋之下延伸得更深，但在方位角各向异性中却没有发现这种差异，这表明在大多数大陆之下，橄榄石晶体的排列在大尺度上优先是水平和方位角随机的。由于大多数大陆位于缓慢移动的板块上，这支持了方位角各向异性在大尺度上与当前板块运动一致的观点，只有快于类似4厘米年（-1）的板块。
We present 3D2015_07Sv, an S wave model of the upper mantle based on the waveform modeling of 1,359,470 Rayleigh waves recorded since 1976. The use of approximate forward theory and modeling allows updating the model with new data on a regular basis. 3D2015_07Sv contains azimuthal anisotropy, achieves a lateral resolution of similar to 600 km, and is consistent with other recent models up to degree 60 in the uppermost 200 km and degree 15 in the transition zone. Although radial anisotropy has been found to extend deeper beneath continents than beneath oceans, we find no such difference for azimuthal anisotropy, suggesting that beneath most continents, the alignment of olivine crystal is preferentially horizontal and azimuthally random at large scale. As most continents are located on slow moving plates, this supports the idea that azimuthal anisotropy aligns at large scale with the present plate motion only for plates faster than similar to 4 cm yr(-1).