Seismic moment tensors of acoustic emissions recorded during laboratory rock deformation experiments: sensitivity to attenuation and anisotropy

0456420 - GFÚ 2017 RIV GB eng J - Journal Article
Stierle, E. - Vavryčuk, Václav - Kwiatek, G. - Charalampidou, E.-M. - Bohnhoff, M.
Seismic moment tensors of acoustic emissions recorded during laboratory rock deformation experiments: sensitivity to attenuation and anisotropy.
Geophysical Journal International. Roč. 205, č. 1 (2016), s. 38-50. ISSN 0956-540X. E-ISSN 1365-246X
R&D Projects: GA ČR(CZ) GAP210/12/1491; GA ČR(CZ) GC16-19751J
Institutional support: RVO:67985530
Keywords : earthquake source observations * seismic anisotropy * seismic attenuation * wave propagation * acoustic properties
Subject RIV: DC - Siesmology, Volcanology, Earth Structure
Impact factor: 2.414, year: 2016

Seismic moment tensors can provide information on the size and orientation of fractures producing acoustic emissions (AEs) and on the stress conditions in the sample. The moment tensor inversion of AEs is, however, a demanding procedure requiring carefully calibrated sensors and accurate knowledge of the velocity model. In field observations, the velocity model is usually isotropic and time independent. In laboratory experiments, the velocity is often anisotropic and time dependent and attenuation might be significant due to opening or closure of microcracks in the sample during loading. In this paper, we study the sensitivity of the moment tensor inversion to anisotropy of P-wave velocities and attenuation. We show that retrieved moment tensors critically depend on anisotropy and attenuation and their neglect can lead to misinterpretations of the source mechanisms. The accuracy of the inversion also depends on the fracturing mode of AEs: tensile events are more sensitive to P-wave anisotropy and attenuation than shear events.
Permanent Link: http://hdl.handle.net/11104/0256947