La fédération
Intranet
Séminaire ISTerre
Local seismic anisotropy from rotational motions of ambient seismic noise
jeudi 5 octobre 2023 - 11h00
Le Tang - Department of Earth and Environmental Sciences, Ludwig-Maximilians-Universität München (LMU), Munich---
We proposed a novel approach capable of measuring local seismic anisotropy from amplitude observations of ambient seismic noise data. Our recent theory demonstrates that the amplitude ratio of rotation-based cross-correlation functions (CCFs) enables retrieving the local phase velocity. Its local sensitivity kernel beneath the rotational seismometer allows us to study the local anisotropy from different azimuthal rotation-based CCFs, avoiding the effect of heterogeneity along the propagation path. We applied this approach to a small seismic array at Pinon Flat Observatory (PFO), Southern California, that can retrieve rotational motions from ambient noise data. The stress- and structure-induced anisotropy are well resolved, which is compatible with other tomography results, providing new constraints and insights into the origin of depth-dependent seismic anisotropy.
Equipe organisatrice : Ondes et structures
Salle Dolomieu, Maison des Géosciences, 38400 Saint Martin d'Hères