The available data of ground

gravity anomaly are the third order gravity network of IGAC showed in the figure 1.

The mascon

gravity anomaly in Figure 6 consists of the well-defined relatively positive 26 mGal anomaly overlying the inferred impact basin.

Either deterministic methods or geostatistical approaches are used to predict the

gravity anomaly values from irregularly scattered survey data.

If this low-density floor material rose to the level of the surrounding pre-lava terrain, the thickness of subsequent lava fill inside the crater would be the same as outside and there would be no

gravity anomaly or, if the highlands material rose higher, a negative one.

where T and g are the tilt angle and

gravity anomaly, respectively.

This cold and rigid geologic body was deduced to be located at a depth of 20-40 km and acted as a significant obstruction to the lower crustal fluid from the west, which has a negative

gravity anomaly and low density.

The second term represents the Global Geopotential Model (GGM) contribution to the approximate geoid height and [DELTA][g.sup.GGM.sub.n] is the Laplace spherical harmonics of the

gravity anomaly calculated from the GGM of degree n, M is the maximum degree of GGM, [b.sub.n] is the least-squares modification parameters.

where [[gamma].sub.m] is taken to be 980 000 mGal; [[gamma].sub.0A] and [[gamma].sub.0B] are normal gravity values on points A and B; [H.sub.m] is the average height of A and B; [(g - [gamma]).sub.m] is the average

gravity anomaly on points A and B.

Lead author Luciano Iess of Sapienza University of Rome said that the Cassini gravity measurements show a negative

gravity anomaly at the south pole that however is not as large as expected from the deep depression detected by the onboard camera.

The connection between the anomaly and the crust structure is revealed by comparing with geophysical fields such as the seismic wave velocity anomaly, the

gravity anomaly, and the lithospheric thermal structure.

W2

Gravity anomaly within SE-NW trending shear zone