Identifying Main Lithospheric Structures in the Eastern Alpine Domain by Joint Inversion of Receiver Function and Surface Wave Measurements for Seismic Anisotropy

阿尔卑斯山脉的造山运动始于新近纪，当时来自欧亚大陆、交错洋盆和微大陆的地壳单元受到亚得里亚海的强烈变形和折叠。东阿尔卑斯山非常适合研究造山运动的全部复杂性，包括地壳分层和变形、推覆体堆叠和侧向逃逸。然而，由于东部阿尔卑斯地区的地壳和深部岩石圈结构仍然没有得到很好的解决，因此其基本过程，特别是驱动力仍然是个谜。认识阿尔卑斯山东部新近纪以来的造山过程的一个先决条件是确定缝合线北部侧向逃逸的意向层和退耦层的形状以及阐明岩石圈深部结构。它仍然是一个悬而未决的问题，如果亚德里亚或欧亚大陆是上层板块或如果造山运动是双重俯冲的结果。此外，地幔岩石圈的性质需要解决，因为它们是量化导致碰撞和造山的构造力的关键。AlpArray -同时部署的密集区域地震阵列-为详细研究造山带深部岩石圈结构提供了一个独特的机会。阿尔卑斯山东部的完整数据集将于2021年提供。基于SPP第一阶段中在单独项目中进行的面波和接收器功能测量，我们将对数据进行联合反演，从而产生岩石圈的高分辨率剪切波速度模型，以解决绝对剪切波速度和主要的地壳和地幔不连续性。我们将扩展随机反演方案，以获得各向同性和各向异性模型及其不确定性。由此产生的高分辨率模型将产生一个东部阿尔卑斯山岩石圈的地震模型。将其与地表的地质记录联系起来，将确定主要深部结构的构造相似性。基于地震观测，我们将与合作伙伴共同开发一个自新近纪开始以来阿尔卑斯山东部岩石圈构造演化的四维综合模型，重点关注研究主题“造山过程中岩石圈的重组”。这将为造山运动的地球动力学数值模拟提供基础。

Mountain building in the Alps started in the Neogene when crustal units derived from Eurasia, inter-vening oceanic basins and microcontinents got strongly deformed and folded by the approaching Adriatic intender. The eastern Alps are ideally suited to study the full complexity of mountain building including crustal delamination and deformation, nappe stacking and lateral escape. The underlying processes and in particular the driving forces remain enigmatic, however, because the crustal and deep lithospheric structure in the eastern Alpine domain are still poorly resolved. A pre-requisite for the understanding of mountain building processes since the Neogene in the eastern Alps is the identification of the shape of the intender and of the decoupling horizon for the lateral escape north of the suture as well as the clarification of the deep lithospheric structure. It re-mains an open question if Adria or Eurasia are the upper plate or if mountain building is the result of bivergent subduction. Also, properties of the mantle lithosphere need to be resolved as they are key for the quantification of tectonic forces causing collision and mountain building. AlpArray – the densest regional seismic array ever deployed contemporaneously - provides a unique opportunity to study the deep lithospheric structure of the orogen in detail. The complete data set for the eastern Alps will be available in 2021. Building on surface-wave and receiver-function measure-ments carried out in separate projects in the first phase of the SPP, we will perform a joint inver-sion of the data that will result in a high-resolution, shear-wave velocity model of the lithosphere to resolve both the absolute shear-wave velocity and major crust and mantle discontinuities. We will extend stochastic inversion schemes to obtain isotropic and anisotropic models and their uncertain-ties. The resulting high-resolution model will yield a seismic model for the eastern Alpine litho-sphere. Relating it to the geological record at the surface, the tectonic affinity of the main deep structures will be identified. Based on seismological observations, we will develop together with co-operation partners focusing on the research theme “Reorganizations of the lithosphere during moun-tain building” a 4D comprehensive model of the tectonic evolution of the lithosphere in the eastern Alps since the beginning of the Neogene. It will provide the basis for numerical geodynamic modelling of mountain building.