Objective 1: Method development
We first developed new methods to measure attenuation and anisotropy using whole Earth oscillations. We studied how much cross-coupling would be needed (Akbarashrafi et al, 2018) and developed a direct spectrum one-step inversion method (Jagt & Deuss, 2021). We also developed new software to collect the data that we needed for our measurements and modeling (Schneider et al, 2022) and new Monte Carlo techniques to use a trans dimensional approach for inner core structure (Brett et al, 2022) and Hamiltonian inversion for mantle density structure (van Tent et al, in prep, 2022).
Objective 2: Data measurement and model development
We then proceeded to make the actual measurements of attenuation (Talavera-Soza & Deuss, in review Geophysical Journal International, 2022) and make a model of 3D velocity and density Koelemeijer et al, Nature Communications, 2017, van Tent et al, in prep, 2022) and 3D attenuation variations in the earth's mantle (Talavera-Soza & Deuss, in review Nature, 2022). We also found that radial modes provide us with new constraints in 1D attenuation but also, quite unexpectedly, on the radial anisotropy structure of the inner core (Talavera-Soza & Deuss, 2020, 2021). The resonance between spheroidal and toroidal modes shows evidence for the existence of strong azimuthal anisotropy in the upper mantle, which will help us in the future to constrain mantle flow (Schneider & Deuss, 2021). because the research on the mantle was going so well, we also extended ATUNE to study outer core structure and its stratification (van Tent et al, 2020) and made new observations of ultra polar body wave paths traveling the Earth's inner core (Brett & Deuss, 2020) and used these two make a new 3D topographic model of the inner core (Brett et al, 2022). We also collaborated in an international research effort to make database of long period multimode surface wave observations and contributed our new data measurements (Moulik et al. 2021).
Objective 3: Model interpretation
Finally, we collaborated with mineral physicists to interpret our 3D mantle attenuation model (Talavera-Soza et al, Nature, in review, 2022) and also collaborated with an expert in paleomagnetism to interpret our 3D inner core anisotropy model and link the different layers to changes in magnetic field reversal rates in the past (de Jong et al, in prep, 2022). We also collaborated with mantle convection modelers in an attempt to constrain the presence of post-perovskite in the lowermost mantle using our 3D mantle models (Koelemeijer et al, 2018).
All our results discussed above have been presented at international conferences, including:
American Geophysical Union Fall meeting in December 2016, 2017, 2018, 2019, 2020, 2021
European Geosciences Union meeting in Vienna in 2016, 2019, 2021, 2022
Studies of Earth's deep Interior meeting (SEDI) in Edmonton, Canada in 2018
Studies of Earth's deep Interior meeting (SEDI) in Zurich, Switzerland in 2022
Gordon Research Conference 'Interior of the Earth', Mount Holyoke, June 2017
The PI has also given a number of invited talk about ATUNE and its results:
CIDER Community workshop, Point Reyes, US, 2016
4D Earth European Space Agency meetings, Noordwijk, The Netherlands, 2017
Inaugural Lecture, Utrecht University, The Netherlands, 2019
ESA 4D deep Earth meeting, online, 2021
American Chemical Society, online, 2022
