M-hm. I won't ask what weird force brings this about.
Instead I'll observe that if it happens as often as danny implies,
there shouldn't be a Hawaiian chain, because the crust would slip
away from the hot-spot before the volcanic cone is more than an
unremarkable lump on the seafloor.
Alternatively, if the great shimmy happens every N million years,
there should be several chains like Hawaii, scattered about the globe,
appropriately staggered in age.
Anton Sherwood *\\* +1 415 267 0685 *\\* DASher@netcom.com