GNGTS 2016 - Atti del 35° Convegno Nazionale

GNGTS 2016 S essione 3.3 591 along the ridges, computed in 3D space by continuing the field at multi-level. We inverted the scaling function for the depth to the bottom of the source by assuming as known the top of the source. In fact, being a well-known problem, the bottom part of the source is the most ambiguous feature to be determined from potential fields. A model is accepted on the basis of the fitting of scaling functions (Fig. 1). Further, using this model the density contrast is calculated by a polynomial fitting between observed gravity field and calculated gravity field at unit density contrast. We estimated -2.01 g/cm 3 . The resulted model is shown in Fig. 2 with solid line, while solid dots represents the fixed vertexes of the body while inversion. Real Case example . We interpreted the gravity profile of Godavari basin, Andhra Pradesh, India by following the same steps as in the synthetic case. This gravity data was taken from the publication of Rao (1990) as shown in Fig. 3a. Field vertical derivative was calculated (Fig. 3a) and data was upward continued up to 2 km in order to calculate ridges (Fig. 3b). Fig. 3c shows the fitness of scaling function for obtained solution. Gravity anomaly is calculated assuming Fig. 2 – Comparison between assumed model (dashed line) and retrieved model (solid line) while solid dots are showing the fixed part of the body while inversion. Fig. 3 – a) Gravity anomaly (blue line) and it’s first vertical derivative (green line); b) calculated ridges in 3D space; c) fitting of observed (blue dotted line) and calculated (red dotted line) scaling functions; d) fitting of gravity anomalies; e) comparison of models.