Annie Souriau

The 2019 Beno Gutenberg Medal is awarded to Annie Souriau in recognition of outstanding contributions to seismological studies of the Earth’s inner and outer cores.

Annie Souriau is an outstanding seismologist who combines deep understanding of observations and experimental data with creative ideas and modelling to address fundamental questions in the Earth’s deep structure. Souriau’s best-known work concerns the Earth’s core. Starting in the 1980s, Souriau brought into discussion subtle but robust anomalous patterns in travel times of seismic phases that traverse or reflect off the Earth’s core. She investigated these anomalies in a number of articles, and proposed and pursued imaginative and elegant models for their explanation. Three significant discoveries concerning the Earth’s inner core were made in the last three decades: (1) the inner core is, to first order, elastically anisotropic with a symmetry axis aligned with the Earth’s rotation axis, (2) the inner core exhibits hemispherical elastic heterogeneity, and (3) the inner core rotates faster than the solid mantle above it. Souriau’s contributions were crucial for the emergence of these discoveries. Her subsequent inner-core studies have carefully and systematically explored the robustness and the details of these inferred exotic characteristics of the inner core, and proposed and tested a range of geophysical models to explain their existence. Souriau’s many contributions extend outside of the inner core. In other innovative work, Souriau has probed and tested the frequently presumed homogeneity of the Earth’s outer core and presented evidence for heterogeneity at its base; she has investigated the role of earthquakes in sustaining the Chandler wobble; and she has explored the connections between mantle heterogeneity and dynamics with the Earth’s surface topography. Souriau’s original contributions to our understanding of the Earth’s deep interior make her a highly deserving recipient of the 2019 EGU Beno Gutenberg Medal.