Non-double-couple moment tensor components and their relation to fluid flow in the West-Bohemia/Vogtland region

西波希米亚/沃格特兰地区以其频繁的板内群活动而闻名，该活动与流体从上地幔流入地壳有关。外力对该地区的地震活动起着重要作用。尤其是初始触发似乎受地壳内流体流动的影响很大。这一知识来源于地震矩张量解，它部分地显示了沃格特兰地区的高非剪切分量(非DC)。然而，可用矩张量的有限数量和确定的非DC分量的模糊性，到目前为止阻碍了对震群活动和流体流动之间的联系的更详细的分析。该项目旨在通过分析完整的地震矩张量，特别是它们的非DC部分，来帮助理解流体流动和地壳变形之间的联系。通过提高非DC部分测定的准确度和精密度，我们能够更好地理解它们对地壳内地震构造过程的影响。我们将采取几种新的方法来实现我们的目标。一是将旋转地面运动的测量纳入其中。因此，我们测量了地震波场的六个分量，而不是只测量了三个分量，这在理论上已经被证明对地震矩张量的波形反演是有价值的。另一种有希望的方法是实现非对称矩张量理论。它能够通过包括破裂期间的物质旋转来更好地解释变形，这将对该地区的构造给予更好的约束。此外，我们还考察了三维结构模型的优点以及各向异性对地震矩张量的非DC部分的分辨率的可能影响。

The West Bohemia/Vogtland region is well known for its frequent intraplate swarm activity connected to fluid flow from the upper mantle into the crust. External forcing plays an important role for the seismic activity of the region. Especially the initial triggering seems to be highly influenced by the fluid flow within the crust. This knowledge is derived from seismic moment tensor solutions, which partly show high non-shear-components (non-DC) for the Vogtland region. However, the limited number of available moment tensors and the ambiguity of the determined non-DC components have so far hampered a more detailed analysis of the connection between swarm activity and fluid flow. This project aims to contribute to the understanding of the connection between fluid flow and crustal deformation by analysing full seismic moment tensors, especially their non-DC part. By improving the accuracy and precision of the determination of non-DC parts, we are able to better understand their implications for seismotectonic processes within the crust. We will take up several new approaches to reach our goals. One is to incorporate measurements of rotational ground motions. Thus, we measure six instead of only three components of the seismic wavefield which already proved to be valuable for waveform inversion for seismic moment tensors in theory. Another promising approach is to implement the theory of the asymmetric moment tensor. It enables to better account for deformation by including material rotations during the rupture which will give better constraints on the tectonics of the region. In addition, we examine the benefits of a 3D structural model and the possible influences of anisotropy to the resolvability of non-DC parts of the seismic moment tensor.