AZIMUTHAL ANISOTROPY IN THE EARTH FROM OBSERVATIONS OF SKS AT GEOSCOPE AND NARS BROADBAND STATIONS
AZIMUTHAL ANISOTROPY IN THE EARTH FROM OBSERVATIONS OF SKS AT GEOSCOPE AND NARS BROADBAND STATIONS
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DOI：
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发表时间：
1989-10
影响因子：
3
通讯作者：
L. Vinnik;V. Farra;B. Romanowicz
中科院分区：
文献类型：
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作者：
L. Vinnik;V. Farra;B. Romanowicz
本文分析了几个GEOSCOPE和NARS阵列宽带台站记录的低频SKS波水平分量的观测结果。SKS分裂是一致的观察和良好的协议，由于横向各向异性与水平轴的方位各向异性的假设，在上地幔下面的接收器。我们设计了一种反演方法，它利用同时在不同方位角的观测，使我们能够获得各向异性快轴的方向以及正交准横波之间的时间延迟的估计。一般来说，获得的快速度的方向，无论是在大西洋周围和太平洋周围的站，似乎与过去和现在的板块运动的方向。
Abstract We have analyzed observations of low-frequency SKS waves recorded on horizontal components at several broadband stations of the GEOSCOPE and NARS arrays. Splitting of SKS is consistently observed and in good agreement with a hypothesis of azimuthal anisotropy due to transverse anisotropy with a horizontal axis, in the upper mantle beneath the receivers. We have designed an inversion method, which takes advantage of observations made simultaneously at different azimuths and which permits us to obtain estimates of the direction of fast axis of anisotropy as well as the time delay between the orthogonal quasi-shear waves. In general, the directions of fast velocity obtained, both for stations around the Atlantic and around the Pacific, appear to be related to directions of past and present plate motions.