Figure 6. The point distribution of the MGH-50 and MGH-2000 gravimetric network
The covered area (the area of the country) is approximately 93000 km2, the number of stations is more than 900 for both the MGH-50 and the MGH-2000 networks, the gravity interval of the country is approximately 350 mGal. The distance between gravimetric stations is roughly 10 km, thus it provides a nice coverage of the country for capturing the relevant features of the gravity field.
For historical reasons, however, most stations of the MGH-50 network have been perished, accordingly, most points of the MGH-2000 are newly established stations. In fact, there are only 13 identical stations of the two networks (see common points in Figure 6). Apart from the change of the gravity by time (which is not striking due to the moderate tectonics of the area), the two networks are meant to present two independent description of the same phenomenon, that is the gravity field of Hungary.
Based on the gravity values of MGH-50 and MGH-2000 networks, gravity has been interpolated onto a common grid, and the difference of the two grids is displayed in Figure 7. Even though the difference between them is in the range of some mGals, there are striking outliers reaching even the 100 mGal value. This is very much, which cannot be interpreted neither with the temporal variations of the gravity field nor with observation errors. This difference is obviously a consequence of the different sampling of the gravity field.