Opening Keynote: What Have We Learned About the Earth’s Interior from Seismology in the Last 40 Years?

Presented by Barbara Romanowicz, University of California, Berkeley
Introduced by SSA President John Townend, Victoria University of Wellington
Moderated by Jeroen Ritsema, University of Michigan and editor-at-large of The Seismic Record

Building upon theoretical foundations laid in the 1970s and owing to the large quantity of high quality digital seismological data accumulating since the early 1980s, our understanding of the earth’s internal structure, as constrained by seismological observations, has rapidly evolved in the last 40 years. From a static view of a planet organized in concentric spherical shells, to the present three dimensional models that reflect its dynamic nature from the upper mantle to the center of the inner core, we now have a clearer picture, among others, about the fate of tectonic slabs or the complex nature of the boundary layer (D”) at the base of the mantle. The formation history of continents, as recorded in the lithosphere of old cratons, is emerging, and evidence for the existence of deeply rooted mantle plumes is mounting. There are live debates about the earth’s inner core dynamics. Combined with insights from geodynamics, mineral physics, geochemistry and other geoscience subfields, we are poised to reconstruct the evolution of our planet through time and the nature of the present-day coupling between the deep interior and plate tectonics. I will review some of the most significant seismological contributions to our knowledge in this field over the last few decades.

Recorded at the SSA 2021 Annual Meeting