Gravity measurements taken on the Filchner Ice Shelf during the Antarctic summer of 1956–57 indicate that the shelf is oscillating; this oscillation has introduced uncertainties in gravity measurements of the order of 0.5 milligal.
It may be possible to utilize this oscillation to study the structure of the shelf in the following manner: in a simple oscillating system displaced a distance x, the relationship between the period of oscillation t, acceleration
By substituting the observed period of oscillation t≃1. min. and
If a gravity survey over the shelf were made, it would be possible to map these small vertical displacements. Possible results from such a survey are as follows:
If we assume that the shelf is oscillating as a simple weighted cantilever with a uniform load, then the amplitudes x 1 and x 2 at two points located distances z 1 and z 2 from the point of support would be related as:Reference Timoshenko and McCullough 1
where l is the length of the cantilever.
From the derived value l one could predict where the shelf was anchored. The existence of islands under the shelf might be indicated if the shelf were anchored on these islands.
Any non-uniform change in the amplitude x = f(z) might be associated with fissures in the shelf where much of the flexing of the shelf would be localized; thus it might be possible to predict the location where calving would take place. Such information might be useful in determining hase sites on shelf ice.
