The negatives of sound

Figure 1

Standard hotspot theory (a), and variations on it (b, c), that might explain McNutt and colleagues’ data¹ on the Cook–Austral chain of volcanoes in the South Pacific. c is the explanation favoured by the authors themselves. Here, a broad region of warm mantle upwelling travels beneath the lithosphere. Cracks in the oceanic plate let magma erupt to form the three chains of volcanic edifices.

Figure 2

Figure 3

Fluff and dust collected from the whispering-gallery, St Paul's Cathedral, London