A shear wave velocity model of the European upper mantle from automated inversion of seismic shear and surface waveforms
A shear wave velocity model of the European upper mantle from automated inversion of seismic shear and surface waveforms
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DOI：
10.1111/j.1365-246x.2012.05613.x
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发表时间：
2012-04
影响因子：
2.8
通讯作者：
C. Legendre;T. Meier;S. Lebedev;W. Friederich;L. Viereck-Götte
中科院分区：
文献类型：
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作者：
C. Legendre;T. Meier;S. Lebedev;W. Friederich;L. Viereck-Götte
我们提出了一个新的，欧洲上地幔的S速度模型，由欧洲和周边地区宽带台站的地震波形反演约束。我们收集了1990年至2007年欧洲所有常设台站的地震图，这些台站的数据是可用的。此外，我们还纳入了临时实验的数据。对表面波和S波形态进行了自动多模反演，以从地震记录中提取结构信息，其形式为具有不相关不确定性的线性方程。然后，根据具有真实地壳的三维参考模型，对这些方程求解地壳和地幔中的地震速度扰动。我们提出了两个版本的模型：一个为整个欧洲上地幔和另一个，具有最高的分辨率，集中在上200公里的地幔下西欧和中欧和环地中海。地幔岩石圈和软流圈都得到了很好的分辨。确定了欧洲和地中海岩石圈-软流圈系统的主要特征。在东欧大陆地幔岩石圈中，最高速度出现在约150 km深度处。没有迹象表明在大约330公里深度以下有一个很深的超声波根。横向变化内的地幔岩石圈的解决以及。金伯利岩的位置与浅地幔岩石圈中S波速度的降低有关。这种异常在元古代和太古代地壳都存在，表明克拉通形成后地幔岩石圈发生了变化。强烈的横向变化的S波速度被发现在西北边缘的EEC，并可能表明侵蚀下的Scandes热的软流圈地幔岩石圈。在西欧之下，托恩奎斯特-泰赛尔带和易北线之间的地幔岩石圈显示出中等的高速度，是一个中间的字符，在欧洲中部的薄岩石圈和岩石圈之间。在中欧，加里东和华力西缝合线与岩石圈-软流圈系统的强烈横向变化无关。中欧和环地中海地区的新生代非造山板内火山活动位于浅软流圈区域，接近岩石圈-软流圈边界深度的变化。从土耳其东部到死海转换断层系统和西奈半岛，在最近火山活动的位置下方，上地幔浅层的速度非常低。低速异常垂直延伸从浅上地幔到过渡区被发现下的中央地块，西奈半岛和死海，加那利群岛和冰岛。
SUMMARY We present a new, S-velocity model of the European upper mantle, constrained by inversions of seismic waveforms from broad-band stations in Europe and surrounding regions. We collected seismograms for the years 1990–2007 from all permanent stations in Europe for which data were available. In addition, we incorporated data from temporary experiments. Automated multimode inversion of surface and S-wave forms was applied to extract structural information from the seismograms, in the form of linear equations with uncorrelated uncertainties. The equations were then solved for seismic velocity perturbations in the crust and mantle with respect to a 3-D reference model with a realistic crust. We present two versions of the model: one for the entire European upper mantle and another, with the highest resolution, focused on the upper 200 km of the mantle beneath western and central Europe and the circum Mediterranean. The mantle lithosphere and asthenosphere are well resolved by both models. Major features of the lithosphere–asthenosphere system in Europe and the Mediterranean are indentified. The highest velocities in the mantle lithosphere of the East European Craton (EEC) are found at about 150 km depth. There are no indications for a deep cratonic root below about 330 km depth. Lateral variations within the cratonic mantle lithosphere are resolved as well. The locations of kimberlites correlate with reduced S-wave velocities in the shallow cratonic mantle lithosphere. This anomaly is present in regions of both Proterozoic and Archean crust, pointing to an alteration of the mantle lithosphere after the formation of the craton. Strong lateral changes in S-wave velocity are found at the northwestern margin of the EEC and may indicate erosion of cratonic mantle lithosphere beneath the Scandes by hot asthenosphere. The mantle lithosphere beneath western Europe and between the Tornquist–Teisseyre Zone and the Elbe Line shows moderately high velocities and is of an intermediate character, between cratonic lithosphere and the thin lithosphere of central Europe. In central Europe, Caledonian and Variscian sutures are not associated with strong lateral changes in the lithosphere–asthenosphere system. Cenozoic anorogenic intraplate volcanism in central Europe and the circum Mediterranean is found in regions of shallow asthenosphere and close to changes in the depth of the lithosphere–asthenosphere boundary. Very low velocities at shallow upper-mantle depths are present from eastern Turkey towards the Dead Sea transform fault system and Sinai, beneath locations of recent volcanism. Low-velocity anomalies extending vertically from shallow upper mantle down to the transition zone are found beneath the Massif Central, Sinai and the Dead Sea, the Canary Islands and Iceland.