Geology Reference
In-Depth Information
Figure 2.9
Effect of a half-metre thick stone wall on the gravity field.
computer programs (or the CG-5 inbuilt program). However, the Earth itself
deforms in response to tidal forces, with a secondary effect on surface
gravity field, and tidal calculations use a correction for Earth elasticity that
is a global average. In extremely accurate work, automatic base stations may
be needed to record the actual variations.
Figure 2.10
Typical (actually 5 to 15 January 1986) tidal variations, in
ยต
Gal.
