Physics for Geologists, Second edition

Gravity 35
example) were to drift west (as the magnetic field apparently does) towards
the low levels south of India they would cause significant changes, includ-
ing the inundation of the Maldive islands, even without global warming.
New Guinea and Australia could be rejoined. The total range is from about
+79 to -104 m.
In greater detail (Figure 3.4) with newer technology, it has been found
that sea-level rises towards oceanic islands, and over sea-mounts. Indeed,
some new sea-mounts have been discovered from local humps of sea-surface
topography. So it can be said that the sea surface has revealed patterns
of gravity variations over the world that would not have been discovered
from terrestrial measurement. The real cause, however, of the low south of
India and perhaps the high over New Guinea has yet to be identified with
confidence.
Copyright 2002 by Richard E. Chapman
Figure 3.4 Sea-surface topography between Madagascar and Mauritius. This
detailed map shows the sea-surface rising to the islands of
Madagascar, RCunion and Mauritius. Contour interval 0.5 m (Cour-
tesy NASAJGoddard Space Flight Center, from Bonneville et al.
1988).