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

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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.