EGU23-7321
https://doi.org/10.5194/egusphere-egu23-7321
EGU General Assembly 2023
© Author(s) 2023. This work is distributed under
the Creative Commons Attribution 4.0 License.

Testing the splitting intensity methodology to retrieve average, dipping, and depth dependent anisotropy from a complex subduction model

Judith M. Confal1, Paola Baccheschi2, Silvia Pondrelli1, Brandon P. VanderBeek3, Foivos Karakostas1, and Manuele Faccenda3
Judith M. Confal et al.
  • 1Istituto Nazionale di Geofisica e Vulcanologia, Bologna, Italy (judithconfal@gmail.com)
  • 2Istituto Nazionale di Geofisica e Vulcanologia, Roma, Italy
  • 3Dipartimento di Geoscienze, Università di Padova, Padua, Italy

Seismic anisotropy measurements provide a lot of information on the deformation and structure of the Earth’s interior, in particular of the upper mantle. Conventional methods of measurement of anisotropy have their limitations, especially regarding depth resolution. Splitting intensity (SI) is a seismic observable, related to the amount of energy on the transverse component waveform and, to a first order, it is linearly related to the elastic perturbations of the medium through the 3-D sensitivity kernels, that can be therefore inverted, allowing a high-resolution image of the upper-mantle anisotropy. Starting from synthetic SKS waveforms, we first derived high-quality SKS splitting intensity measurements; then we used the splitting intensity data as input into tomographic inversion. This approach enables high‐resolution tomographic images of horizontal upper‐mantle anisotropy through recovering vertical and lateral changes in anisotropy and represents a propaedeutic step to the real cases of subduction settings. Additionally, this approach was able to detect regions of strong dipping anisotropy by allowing a 360° periodic dependence of the splitting vector. Single and thick layers of dipping angles between 30 and 60° are clearly represented with a high dt2 value, while double layers or nearly vertical dips are more difficult to identify.

How to cite: Confal, J. M., Baccheschi, P., Pondrelli, S., VanderBeek, B. P., Karakostas, F., and Faccenda, M.: Testing the splitting intensity methodology to retrieve average, dipping, and depth dependent anisotropy from a complex subduction model, EGU General Assembly 2023, Vienna, Austria, 24–28 Apr 2023, EGU23-7321, https://doi.org/10.5194/egusphere-egu23-7321, 2023.