In contrast to the magnetic anomalies, a clear contrast between both
terranes is not apparent in the map of the Bouguer anomalies of
Thailand displayed in Fig. 2b (Bonvalot et al., 2012). The overall values
of the Bouguer anomalies are relatively low in the global scale and
range between −150 mGal in the north to less than 50 mGal in the
south (Fig. 2b). The low Bouguer anomalies in the north and west of
the country are associated with the high elevation topography there.
The low values in the south are also associated with low topography
(Figs. 1 and 2b ). The contrast between the Bouguer anomalies and
the non-isostatic topography again occurs in the KP-ICT region
(Fig. 2b). The elevation of the Khorat Plateau is just 100–250 m which
should produce the Bouguer anomalies of around −10 to −20 mGal
(Milsom, 2011) but their actual mean values are lower at around −50
mGal. Milsom (2011) suggested that the overcompensation of the
Khorat Plateau may be due to the fact that it is rising at present.