Spatial and temporal seismic imaging of fluid migration through the crust in the W-Bohemia/Vogtland earthquake swarm area

W-Bohemia/Vogtland地区具有空间聚集性地震活动特征，典型震源深度为6 ~ 12 km。观测到与地震活动相关的上地幔衍生流体的脱气，以及排放气体的数量和组成、同位素组成和震源过程的时间变化。从震源研究和事件间关系中发现了流体控制地震触发的证据。上地壳和壳幔过渡带的流体储层已被提出，但对它们的直接观测仍然缺失。震中和气泉在空间上是分开的，流体流向地表的途径以及它们与地壳地震结构的关系仍未得到解决。这些特征使埃格尔裂谷/沃格特兰地区成为科学钻探的主要地点。在这个项目中，地壳地震结构和流体动力学的时空成像将通过各种方法实现。我们将测试流体储层的假设存在，并使用地震速度和衰减层析成像以及尾波研究来估计其空间范围。我们将测量应力和流体动力学的时间演变，提供有关群震周期中上地壳变化的信息。该项目提供的3D和4D地震模型将限制在Eger裂谷系统中选择最佳ICDP钻井位置的决策。

The W-Bohemia/Vogtland region is characterized by spatially clustered swarm earthquake activity with a typical source depth of 6-12 km. Degassing of upper mantle derived fluids, correlating with seismicity, is observed as well as temporal variations in the amount and composition of the emitted gas, isotope composition, and in earthquake source processes. Evidence for fluid-controlled earthquake triggering was found from earthquake source studies and inter-event relationships. Fluid reservoirs have been proposed for the upper crust as well as for the crust-mantle transition zone, but their direct observation is still missing. Epicentres and gas springs are spatially separated and the pathways of fluids to the surface remain unresolved as are their relations to the crustal seismic structure. These features make the Eger Rift/Vogtland area a prime site for scientific drilling. In this project spatial and temporal imaging of crustal seismic structures and fluid dynamics will be achieved by various approaches. We will test the hypothetical existence of a fluid reservoir and estimate its spatial extent using seismic velocity and attenuation tomography as well as coda studies. We will measure the temporal evolution of stress and fluid dynamics giving information about changes in the upper crust during a swarm earthquake cycle. The 3D and 4D seismological models delivered by this project will constrain the decision for an optimal ICDP drilling location in the Eger Rift system.