Seismic anisotropy and attenuation retrieved from waveform recordings of acoustic emissions and observations of natural and induced seismicity

地震矩张量分析是地震学和岩石物理学中一个发展迅速的领域。因此，通常假设各向同性介质属性。然而，地震观测证实，大多数岩石是各向异性和衰减。这些属性共同影响传播波场，也影响震源的属性。特别是，地震矩张量的反演更加复杂，并且不可能直接解释各向异性介质中的矩张量。该项目的主要目标是开发确定地质结构地震各向异性的新方法，并将这些方法应用于具有自然和诱发地震活动的地震活跃区，以改进地震力学模型，从而更好地确定震源区的特征。通过对各向异性和粘弹性介质的矩张量反演，将得到高质量的矩张量和源张量。在各向异性和衰减介质中评估完整的矩和源张量将允许获得关于裂缝的几何形状、裂缝过程和裂缝岩石的性质的更详细的信息。该项目的成果将在碳氢化合物和地热储层诱发地震活动方面得到工业应用，并详细了解火山和地震活跃地区危险增加的情况。在各向异性和衰减介质中计算完整的矩张量将使我们能够获得关于裂缝几何形状、裂缝过程和裂缝岩石性质的更详细的信息。

Analysis of seismic moment tensors is a rapidly developing field in earthquake seismology and rock physics. Hereby, isotropic medium properties are usually assumed. However, seismic observations confirm that most rocks are anisotropic and attenuating. These properties jointly affect the propagating wavefields but also properties of seismic sources. In particular, the inversion for the seismic moment tensors is more complicated and a straightforward interpretation of moment tensors in anisotropic media is not possible. The main objective of this project is to develop new methods for determining seismic anisotropy of geological structures and to apply these methods to seismically active regions with natural and induced seismicity in order to refine seismo-mechanical models towards an improved characterization of the focal zone. High quality moment and source tensors will be retrieved by applying a new method of moment tensor inversion for anisotropic and viscoelastic media. Evaluating the complete moment and source tensors in anisotropic and attenuating media will allow getting more detailed information on the geometry of fractures, the fracture processes and on the properties of the fractured rock. The results of the project will find industrial applications related to induced seismicity in hydrocarbon and geothermal reservoirs as well as detailed knowledge about increased hazard in volcanic and seismically active regions. Evaluating the complete moment tensors in anisotropic and attenuating media will allow us to get more detailed information on the geometry of fractures, the fracture processes and on the properties of fractured rock.