Two-dimensional expressions and graphics to obtain geoid undulations in isostatic structures.

CROVETTO C.- INTROCASO A.

Estambul (Turquía).

Simposio; 1st. International Symposium of the International Gravity Field Service (IGFS); 2006

Traditionally, isostatic studies were made comparing observed gravity anomalies with gravity anomalies from a comparison theoretical model. Nowadays, the possibility to easily obtain geoid undulations introduces an alternative tool to make that kind of studies. The methodology is the same as with traditional gravimetry: to compare observed geoid undulations with the ones produced by a theoretical model in the same wavelengths. Theoretical geoid undulations are obtained via three-dimensional integrations, which are usually slow calculus. This fact promotes the use of approximations to obtain geoid undulations faster. In this work, we evaluate two-dimensional approximations to compute geoid undulations due to balanced geological structures (Airy and Pratt models), showing the benefits of these expressions over the one-dimensional ones. We present geoid undulations level contours for different isostatic hypothesis, which can be used to make quick estimations of isostatic undulations simply knowing the structure’s height (in the case of elevations) or depth (in sedimentary basins) and width.