Carissimi Associati SGI,
Carissimi Soci Società Associate,
su indicazione del Prof. Rodolfo Carosi (Università di Torino e Presidente SGI) vi segnaliamo l'ultimo podcast di Geology Bites (Conversations about geology with researchers making key contributions to our understanding of the Earth and the Solar System):
Di seguito troverete il messaggio dell'ideatore, Oliver Strimpel, e il link al sito web di Geology Bites.
Cordiali saluti,
La Segreteria SGI
Hello, listeners,
I've just posted an episode with Bernhard Steinberger, a geophysicist at the GFZ Helmholtz Centre for Geosciences in Potsdam, on whether hotspots are fixed.
Hotspots, like the one under Hawaii, leave a trail of volcanoes and seamounts as the plate drifts over them. Because the plumes feeding them rise from deep in the mantle, hotspots were long assumed to sit still — and therefore useful as a fixed grid against which to measure how the plates move. But I learned that this turns out not to be true, and yet the method survives. Every hotspot has its own proper motion, and no two move in concert — but because Steinberger and his colleagues can model those motions, the hotspots can still be used to define a reference frame, motion and all, against which to establish how the plates move relative to the mantle.
I'll confess that I found keeping track of all the frames of reference tricky — plates moving over the mantle, hotspots moving through it, and the whole solid Earth tipping over relative to the spin axis (true polar wander). But Steinberger explains it well.
As always, go to geologybites.com to see the illustrations that support the episode. I hope you enjoy listening.
Best wishes,
Oliver