We study the crustal structure under the Eastern and Southern Alps using ambient noise tomography. We use cross-correlations of ambient seismic noise between pairs of 71 permanent stations and 19 stations of the Eastern Alpine Seismic Investigation (EASI) profile to derive new 3D shear velocity models for the crust. Continuous records from 2014 and 2015 are cross-correlated to estimate Green's functions of Rayleigh and Love waves propagating between the station pairs. Group velocities extracted from the cross-correlations are inverted to obtain isotropic 3D Rayleigh- and Love-wave shear-wave velocity models. Our models image several velocity anomalies and contrasts and reveal details of the crustal structure. Velocity variations at short periods correlate very closely with the lithologies of tectonic units at the surface and projected to depth. Low-velocity zones, associated with the Po and Molasse sedimentary basins, are imaged well to the south and north of the Alps, respectively. We find large high-velocity zones associated with the crystalline basement that forms the core of the Tauern Window. Small-scale velocity anomalies are also aligned with geological units of the Austroalpine nappes. Clear velocity contrasts in the Tauern Window along vertical cross sections of the velocity model show the depth extent of the tectonic units and their bounding faults. A mid-crustal velocity contrast is interpreted as a manifestation of intracrustal decoupling in the Eastern Alps that accommodated eastward escape of the Alcapa block.

中文翻译：

---

通过环境噪声层析成像，在东部和南部阿尔卑斯山下面的地壳结构

我们使用环境噪声层析成像技术研究东阿尔卑斯山和南阿尔卑斯山下的地壳结构。我们使用东部高山地震勘探（EASI）剖面的71个永久站点和19个站点对之间的环境地震噪声的互相关来得出地壳的新3D剪切速度模型。2014年和2015年的连续记录相互关联，以估计格林在电台对之间传播的瑞利波和洛夫波的功能。将从互相关中提取的组速度进行倒置，以获得各向同性的3D瑞利波和洛夫波切变波速度模型。我们的模型成像了几个速度异常和对比，并揭示了地壳结构的细节。短期内的速度变化与地表构造单元的岩性密切相关，并投射到深度。与Po和Molasse沉积盆地相关的低速带分别在阿尔卑斯山的南部和北部成像良好。我们发现与形成Tauern窗核心的晶体基底相关的高速区域。小规模的速度异常也与澳大利亚阿尔卑斯山的尿布的地质单位保持一致。牛头窗沿速度模型的垂直横截面清晰的速度对比显示了构造单元的深度范围及其边界断层。地壳中部速度对比被解释为东阿尔卑斯山壳内解耦的一种表现，它适应了阿尔卡帕地块的东逃。我们发现与形成Tauern窗核心的晶体基底相关的高速区域。小规模的速度异常也与澳大利亚阿尔卑斯山的尿布的地质单位保持一致。牛头窗沿速度模型的垂直横截面清晰的速度对比显示了构造单元的深度范围及其边界断层。地壳中部速度对比被解释为东阿尔卑斯山壳内解耦的一种表现，它适应了阿尔卡帕地块的东逃。我们发现与形成Tauern窗核心的晶体基底相关的高速区域。小规模的速度异常也与澳大利亚阿尔卑斯山的尿布的地质单位保持一致。牛头窗沿速度模型的垂直横截面清晰的速度对比显示了构造单元的深度范围及其边界断层。地壳中部速度对比被解释为东阿尔卑斯山壳内解耦的一种表现，它适应了阿尔卡帕地块的东逃。牛头窗沿速度模型的垂直横截面清晰的速度对比显示了构造单元的深度范围及其边界断层。地壳中部速度对比被解释为东阿尔卑斯山壳内解耦的一种表现，它适应了阿尔卡帕地块的东逃。牛头窗沿速度模型的垂直横截面清晰的速度对比显示了构造单元的深度范围及其边界断层。地壳中部速度对比被解释为东阿尔卑斯山壳内解耦的一种表现，它适应了阿尔卡帕地块的东逃。