Ecco quà il brano sulla nutazione.....
It has been shown how plate motions followed and follow a
mainstream (Fig. 2) that can be reconstructed from ocean magnetic
anomalies and space geodesy data (Doglioni, 1990; Crespi et al., 2007).
This flow is polarized toward the “west” relative to the mantle. The net
rotation is only an average value in the deep hotspot reference frame,
but it rises to a complete polarization in the shallow hotspot reference
frame (Fig. 2). The latitude range of the net rotation equator is about
the same of the Moon maximum declination range (±28°) during the
nutation period (≈18.6 yr). Further indications come from the fact
that the induced geopotential variations and the solid Earth tide
modeling (McCarthy and Petit, 2004) generate maximum amplitudes
of the Earth bulges (≈30 cm) propagating progressively within the
same latitude range. In particular, the track of the semidiurnal bulge
crest is about directed from E to W, as small circles moving from
latitudes 28° to 18°, when the Moon moves from maximum to min-
imum declinations (the same happens at negative latitudes for the
opposite bulge), thus suggesting a role of rotational and tidal drag
effects
Quindi la luna trascina la litosfera e questa si deforma seguendo i suoi moti, ciclo dei nodi compreso?
