The Doornbos Memorial Prize is presented to a young scientist by the Committee on Studies of the Earth’s Deep Interior (SEDI) of the International Union of Geodesy and Geophysics (IUGG), in association with their biennial meetings, for outstanding work on the Earth’s deep interior. It is given in honor of the Dutch seismologist, Durk Doornbos.

And this year’s awardee is … former TIMEleSS post-doc John Keith Magali ! John was awarded the prize for his multidisciplinary and original approach combining dynamics and mineral physics to understand and predict seismic structures, in particular near subduction zones.

This prize arises specifically from the work John Keith Magali started during his PhD in Lyon and his following post-doc with TIMEleSS on how to integrate high-pressure experiment results with geodynamical models and compare the model predictions with seismic observations. This is a nice conclusion to the project, 8 years after it started !

Congratulations John !

We have a new publication ! In his work published in AGU’s Geochemistry, Geophysics, Geosystems, J.K. Magali investigates the Influence of Pressure, Phase Transitions, and Water on Large-Scale Seismic Anisotropy Underneath a Subduction Zone.

In fact, subduction deep inside the Earth’s mantle causes the surrounding mantle to deform according to the movement and pressure exerted by the plates. This influences the alignment of minerals making up the mantle, which in turn, affects the speed and direction of seismic waves known as seismic anisotropy.

In this publication, we investigate the role of pressure in the upper mantle and water in the transition zone on large‐scale seismic anisotropy across a subduction zone. In the upper mantle, we show that the patterns of anisotropy at places where deformation is presumed to be large are affected by changes in pressure. In the transition zone, anisotropy tends to favor a wetter environment.

Want to know more ? The full reference is here : Magali, J. K., Thomas, C., Ledoux, E. E., Capdeville, Y., & Merkel, S. (2025). On the influence of pressure, phase transitions, and water on large-scale seismic anisotropy underneath a subduction zone. Geochemistry, Geophysics, Geosystems, 26, e2024GC011827. https://doi.org/10.1029/2024GC011827.

On June 6, 2024, Federic Rochira defended her thesis! She presented her work for 30 minutes, followed by 60 minutes of oral examination, in front of an international committee composed of Tine Thomas as first examiner, Sebastian Rost (University of Leeds) as second examiner, and Alexander Kappes (University of Münster) as third examiner.

In her work, Federica investigated the presence of seismic structures in the Earth’s mantle and their effect on seismic wave paths, using a combination of seismic signals that are thought to travel along the predicted great circle path, between the source and the receiver, as well as signals traveling off the great circle path direction. To better constrain depth and location of mantle reflectors, she took into account directivity parameters of seismic signals, not yet widely used, as well as their traveltime.

Results show the advantages and necessity of using directivity information of seismic signals to detect regional-scale structures in the mantle associated with both subducted slabs and upwelling plumes, as well as mantle discontinuities. Ignoring the directional information, estimated location and depth of reflectors might be inaccurate and contribute to a misleading interpretation of mantle structures in terms of Earth’s dynamics and mineralogy.

She is now a Doctor of the University of Münster. Congratulations!

Yet another publication from the TIMEleSS team! Former TIMEleSS PhD student Jeff Gay has a new paper entitled Depth Dependent Deformation and Anisotropy of Pyrolite in the Earth’s Lower Mantle in the latest issue of Geophysical Research Letters.

Seismologists rely on observable data to construct models that describe the dynamic state of the Earth’s lower mantle. These models, however, require constraints such as mantle composition and material behavior at high pressures and temperatures, which can be provided through experimental mineral physics.

In this study, we use a high pressure devices and X-rays to impose deformation and image the state of our sample with increasing pressure and temperature. We are able to extract information of individual mineral grains within our assemblage, such as the number of grains per phase and their orientations.

Using this experimental data, we identify three regimes of grain orientations in bridgmanite in the lower mantle, corresponding to

1. transformation from lower pressure phases,
2. deformation below ~50 GPa,
3. deformation above ~50 GPa.

With this information, we are able to make predictions about how seismic waves travel and behave based on the deformation state of the lower mantle.