Ana Ferreira on Seeing Flows in the Mantle
Listen now
Does the pull of a subducting slab drive plate motions?  Or is it the upwellings of convection cells in the mantle?  We now have a new way to shed light on this question.  It's called seismic anisotropy, which is the spreading out of seismic waves according to their direction of polarization.  This happens when the mantle through which the waves travel has crystals which are preferentially aligned, and that occurs when there is deformation or flow going on.  So we can work backwards to use the observed dispersion of seismic wave arrival times to infer flow patterns in the mantle.  In the podcast, Ana Ferreira explains how we do this, and describes our first views of an interaction between a mantle plume pushing up into and flowing around a subducting plate in the southwest Pacific.  But, despite the vigor of such plumes, she concludes that it is probably the pull of the sinking slabs that is still the primary driver of plate motions. Ana Ferreira is Professor of Seismology at University College, London.   She collects and analyzes seismic data from around the world, focusing particularly on seismic anisotropy. See her maps of mantle flow at   If you're enjoying the series, I'd be grateful if you could rate the podcast and leave a review.
More Episodes
Complex life did not start in the Cambrian - it was there in the Ediacaran, the period that preceded the Cambrian. And the physical and chemical environment that prevailed in the early to middle Cambrian may well have arisen at earlier times in Earth history. So what exactly was the Cambrian...
Published 06/08/24
Published 06/08/24
Jupiter's innermost Galilean moon, Io, is peppered with volcanos that are erupting almost all the time. In this episode, Scott Bolton, Principal Investigator of NASA's Juno mission to Jupiter, describes what we're learning from this space probe. Since its arrival in 2017, its orbit around...
Published 05/25/24