Influence of systematic errors in density determination from gravimetric data

Density values recently obtained from bidimensional versions of the Nettleton and Parasnis methods showed some discrepancies from those commonly employed for the reduction of gravity data in the Murgian area (Apulia, Southern Italy). This suggested the need to re-examine the procedures adopted and test the influence of data processing methods on density determinations. Particular attention was given to the fictitious correlations that systematic errors can generate between topography and Bouguer anomalies in small scale surveys. The tests showed that the main problem is the presence of errors correlated with elevation or topographic correction, particularly if the range of these errors is a significant fraction of the latter (5% or more). However normal care in data processing should ensure reliable results, and in the case of surveys specifically devoted to density determination (for example in technical geological problems) the choice of correction parameters can even be less crucial than in normal surveys.